getting ClassDefNotFound on task Manager?

hi... i'm trying to develop a plugin for a task provider however, when i try to launch the sand box i get in the console:

C:\Java\jdk1.6.0\bin\java -Xmx512m -Xms256m -XX:MaxPermSize=250m "-Xbootclasspath/a:C:/Program Files (x86)/JetBrains/IntelliJ IDEA 11.1.3\lib\boot.jar" -Didea.config.path=C:\Users\Elhanan\.IntelliJIdea11\system\plugins-sandbox\config -Didea.system.path=C:\Users\Elhanan\.IntelliJIdea11\system\plugins-sandbox\system -Didea.plugins.path=C:\Users\Elhanan\.IntelliJIdea11\system\plugins-sandbox\plugins -Didea.launcher.port=7534 "-Didea.launcher.bin.path=C:\Program Files (x86)\JetBrains\IntelliJ IDEA 11.1.3\bin" -Dfile.encoding=windows-1255 -classpath "C:\Java\jdk1.6.0\lib\tools.jar;C:/Program Files (x86)/JetBrains/IntelliJ IDEA 11.1.3\lib\idea_rt.jar;C:/Program Files (x86)/JetBrains/IntelliJ IDEA 11.1.3\lib\idea.jar;C:/Program Files (x86)/JetBrains/IntelliJ IDEA 11.1.3\lib\bootstrap.jar;C:/Program Files (x86)/JetBrains/IntelliJ IDEA 11.1.3\lib\extensions.jar;C:/Program Files (x86)/JetBrains/IntelliJ IDEA 11.1.3\lib\util.jar;C:/Program Files (x86)/JetBrains/IntelliJ IDEA 11.1.3\lib\openapi.jar;C:/Program Files (x86)/JetBrains/IntelliJ IDEA 11.1.3\lib\trove4j.jar;C:/Program Files (x86)/JetBrains/IntelliJ IDEA 11.1.3\lib\jdom.jar;C:/Program Files (x86)/JetBrains/IntelliJ IDEA 11.1.3\lib\log4j.jar;C:\Program Files (x86)\JetBrains\IntelliJ IDEA 11.1.3\lib\idea_rt.jar" com.intellij.rt.execution.application.AppMain com.intellij.idea.Main
[   6618]  ERROR - ij.components.ComponentManager -  [Plugin: com.intellij.tasks]
com.intellij.diagnostic.PluginException:  [Plugin: com.intellij.tasks]
 at com.intellij.openapi.components.impl.ComponentManagerImpl$ComponentsRegistry.a(ComponentManagerImpl.java:465)
 at com.intellij.openapi.components.impl.ComponentManagerImpl$ComponentsRegistry.a(ComponentManagerImpl.java:431)
 at com.intellij.openapi.components.impl.ComponentManagerImpl$ComponentsRegistry.access$000(ComponentManagerImpl.java:417)
 at com.intellij.openapi.components.impl.ComponentManagerImpl.a(ComponentManagerImpl.java:101)
 at com.intellij.openapi.components.impl.ComponentManagerImpl.initComponents(ComponentManagerImpl.java:342)
 at com.intellij.openapi.components.impl.ComponentManagerImpl.init(ComponentManagerImpl.java:85)
 at com.intellij.openapi.project.impl.ProjectImpl.init(ProjectImpl.java:293)
 at com.intellij.openapi.project.impl.ProjectManagerImpl.a(ProjectManagerImpl.java:277)
 at com.intellij.openapi.project.impl.ProjectManagerImpl.a(ProjectManagerImpl.java:330)
 at com.intellij.openapi.project.impl.ProjectManagerImpl.access$400(ProjectManagerImpl.java:80)
 at com.intellij.openapi.project.impl.ProjectManagerImpl$9.compute(ProjectManagerImpl.java:549)
 at com.intellij.openapi.project.impl.ProjectManagerImpl$9.compute(ProjectManagerImpl.java:545)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl$4.run(ProgressManagerImpl.java:256)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl$TaskRunnable.run(ProgressManagerImpl.java:469)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl$6.run(ProgressManagerImpl.java:288)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl$2.run(ProgressManagerImpl.java:178)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:218)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl.runProcess(ProgressManagerImpl.java:169)
 at com.intellij.openapi.application.impl.ApplicationImpl$8$1.run(ApplicationImpl.java:641)
 at com.intellij.openapi.application.impl.ApplicationImpl$6.run(ApplicationImpl.java:434)
 at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
 at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
 at java.util.concurrent.FutureTask.run(FutureTask.java:138)
 at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
 at java.lang.Thread.run(Thread.java:662)
 at com.intellij.openapi.application.impl.ApplicationImpl$1$1.run(ApplicationImpl.java:145)
Caused by: java.lang.ExceptionInInitializerError
 at java.lang.Class.forName0(Native Method)
 at java.lang.Class.forName(Class.java:247)
 at com.intellij.openapi.components.impl.ComponentManagerImpl$ComponentsRegistry.a(ComponentManagerImpl.java:441)
 ... 26 more
Caused by: java.lang.ArrayStoreException
 at java.lang.System.arraycopy(Native Method)
 at java.util.ArrayList.toArray(ArrayList.java:306)
 at com.intellij.openapi.extensions.impl.ExtensionPointImpl.getExtensions(ExtensionPointImpl.java:174)
 at com.intellij.openapi.extensions.Extensions.getExtensions(Extensions.java:105)
 at com.intellij.openapi.extensions.Extensions.getExtensions(Extensions.java:92)
 at com.intellij.tasks.TaskManager.<clinit>(TaskManager.java:96)
 ... 29 more
[   6623]  ERROR - ij.components.ComponentManager - IntelliJ IDEA 11.1.3  Build #IU-117.798
[   6623]  ERROR - ij.components.ComponentManager - JDK: 1.6.0_35
[   6623]  ERROR - ij.components.ComponentManager - VM: Java HotSpot(TM) Client VM
[   6623]  ERROR - ij.components.ComponentManager - Vendor: Sun Microsystems Inc.
[   6623]  ERROR - ij.components.ComponentManager - OS: Windows 7
[   6623]  ERROR - ij.components.ComponentManager - Last Action:  
[   6624]  ERROR - ij.components.ComponentManager - Original exception:  
java.lang.ExceptionInInitializerError
 at java.lang.Class.forName0(Native Method)
 at java.lang.Class.forName(Class.java:247)
 at com.intellij.openapi.components.impl.ComponentManagerImpl$ComponentsRegistry.a(ComponentManagerImpl.java:441)
 at com.intellij.openapi.components.impl.ComponentManagerImpl$ComponentsRegistry.a(ComponentManagerImpl.java:431)
 at com.intellij.openapi.components.impl.ComponentManagerImpl$ComponentsRegistry.access$000(ComponentManagerImpl.java:417)
 at com.intellij.openapi.components.impl.ComponentManagerImpl.a(ComponentManagerImpl.java:101)
 at com.intellij.openapi.components.impl.ComponentManagerImpl.initComponents(ComponentManagerImpl.java:342)
 at com.intellij.openapi.components.impl.ComponentManagerImpl.init(ComponentManagerImpl.java:85)
 at com.intellij.openapi.project.impl.ProjectImpl.init(ProjectImpl.java:293)
 at com.intellij.openapi.project.impl.ProjectManagerImpl.a(ProjectManagerImpl.java:277)
 at com.intellij.openapi.project.impl.ProjectManagerImpl.a(ProjectManagerImpl.java:330)
 at com.intellij.openapi.project.impl.ProjectManagerImpl.access$400(ProjectManagerImpl.java:80)
 at com.intellij.openapi.project.impl.ProjectManagerImpl$9.compute(ProjectManagerImpl.java:549)
 at com.intellij.openapi.project.impl.ProjectManagerImpl$9.compute(ProjectManagerImpl.java:545)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl$4.run(ProgressManagerImpl.java:256)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl$TaskRunnable.run(ProgressManagerImpl.java:469)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl$6.run(ProgressManagerImpl.java:288)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl$2.run(ProgressManagerImpl.java:178)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:218)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl.runProcess(ProgressManagerImpl.java:169)
 at com.intellij.openapi.application.impl.ApplicationImpl$8$1.run(ApplicationImpl.java:641)
 at com.intellij.openapi.application.impl.ApplicationImpl$6.run(ApplicationImpl.java:434)
 at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
 at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
 at java.util.concurrent.FutureTask.run(FutureTask.java:138)
 at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
 at java.lang.Thread.run(Thread.java:662)
 at com.intellij.openapi.application.impl.ApplicationImpl$1$1.run(ApplicationImpl.java:145)
Caused by: java.lang.ArrayStoreException
 at java.lang.System.arraycopy(Native Method)
 at java.util.ArrayList.toArray(ArrayList.java:306)
 at com.intellij.openapi.extensions.impl.ExtensionPointImpl.getExtensions(ExtensionPointImpl.java:174)
 at com.intellij.openapi.extensions.Extensions.getExtensions(Extensions.java:105)
 at com.intellij.openapi.extensions.Extensions.getExtensions(Extensions.java:92)
 at com.intellij.tasks.TaskManager.<clinit>(TaskManager.java:96)
 ... 29 more
[  12837]  ERROR - penapi.actionSystem.impl.Utils - update failed for AnAction with ID=tasks.switch.toolbar
java.lang.NoClassDefFoundError: Could not initialize class com.intellij.tasks.TaskManager
 at com.intellij.tasks.actions.SwitchTaskCombo.update(SwitchTaskCombo.java:90)
 at com.intellij.openapi.actionSystem.ex.ActionUtil.performDumbAwareUpdate(ActionUtil.java:98)
 at com.intellij.openapi.actionSystem.impl.Utils.a(Utils.java:163)
 at com.intellij.openapi.actionSystem.impl.Utils.expandActionGroup(Utils.java:124)
 at com.intellij.openapi.actionSystem.impl.Utils.expandActionGroup(Utils.java:84)
 at com.intellij.openapi.actionSystem.impl.Utils.expandActionGroup(Utils.java:142)
 at com.intellij.openapi.actionSystem.impl.ActionToolbarImpl$2.run(ActionToolbarImpl.java:815)
 at com.intellij.openapi.wm.impl.FocusManagerImpl.a(FocusManagerImpl.java:615)
 at com.intellij.openapi.wm.impl.FocusManagerImpl.g(FocusManagerImpl.java:596)
 at com.intellij.openapi.wm.impl.FocusManagerImpl.e(FocusManagerImpl.java:566)
 at com.intellij.openapi.wm.impl.FocusManagerImpl.access$200(FocusManagerImpl.java:55)
 at com.intellij.openapi.wm.impl.FocusManagerImpl$7.run(FocusManagerImpl.java:465)
 at com.intellij.util.ui.UIUtil.invokeLaterIfNeeded(UIUtil.java:1762)
 at com.intellij.openapi.wm.impl.FocusManagerImpl.doWhenFocusSettlesDown(FocusManagerImpl.java:443)
 at com.intellij.openapi.actionSystem.impl.ActionToolbarImpl.a(ActionToolbarImpl.java:861)
 at com.intellij.openapi.actionSystem.impl.ActionToolbarImpl.access$400(ActionToolbarImpl.java:56)
 at com.intellij.openapi.actionSystem.impl.ActionToolbarImpl$MyTimerListener.run(ActionToolbarImpl.java:769)
 at com.intellij.openapi.actionSystem.impl.WeakTimerListener.run(WeakTimerListener.java:50)
 at com.intellij.openapi.actionSystem.impl.ActionManagerImpl$MyTimer.a(ActionManagerImpl.java:1242)
 at com.intellij.openapi.actionSystem.impl.ActionManagerImpl$MyTimer.a(ActionManagerImpl.java:1231)
 at com.intellij.openapi.actionSystem.impl.ActionManagerImpl$MyTimer.actionPerformed(ActionManagerImpl.java:1212)
 at javax.swing.Timer.fireActionPerformed(Timer.java:291)
 at javax.swing.Timer$DoPostEvent.run(Timer.java:221)
 at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
 at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:666)
 at java.awt.EventQueue.access$400(EventQueue.java:81)
 at java.awt.EventQueue$2.run(EventQueue.java:627)
 at java.awt.EventQueue$2.run(EventQueue.java:625)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
 at java.awt.EventQueue.dispatchEvent(EventQueue.java:636)
 at com.intellij.ide.IdeEventQueue.e(IdeEventQueue.java:699)
 at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:538)
 at com.intellij.ide.IdeEventQueue.b(IdeEventQueue.java:420)
 at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:378)
 at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
 at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
 at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
 at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
 at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
 at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)