SBT import Play 2 project fails on 14 RC3 Community

When I try to use the SBT import functionality on a Play 2 project, it silently fails. What I found in the log is this:

2014-11-02 07:31:15,812 [ 283191]  ERROR - tartup.impl.StartupManagerImpl - Can't deserialize target data of key 'Play2ProjectData'. Given class loaders: [com.intellij.util.lang.UrlClassLoader@35ab28fe, com.intellij.util.lang.UrlClassLoader@35ab28fe]
java.lang.IllegalStateException: Can't deserialize target data of key 'Play2ProjectData'. Given class loaders: [com.intellij.util.lang.UrlClassLoader@35ab28fe, com.intellij.util.lang.UrlClassLoader@35ab28fe]
 at com.intellij.openapi.externalSystem.model.DataNode.prepareData(DataNode.java:182)
 at com.intellij.openapi.externalSystem.model.DataNode.getData(DataNode.java:91)
 at com.intellij.openapi.externalSystem.model.DataNode.toString(DataNode.java:273)
 at java.lang.String.valueOf(String.java:2826)
 at java.lang.StringBuilder.append(StringBuilder.java:115)
 at java.util.AbstractCollection.toString(AbstractCollection.java:422)
 at java.util.Formatter$FormatSpecifier.printString(Formatter.java:2794)
 at java.util.Formatter$FormatSpecifier.print(Formatter.java:2677)
 at java.util.Formatter.format(Formatter.java:2433)
 at java.util.Formatter.format(Formatter.java:2367)
 at java.lang.String.format(String.java:2769)
 at com.intellij.openapi.externalSystem.service.project.manage.ProjectDataManager.importData(ProjectDataManager.java:109)
 at com.intellij.openapi.externalSystem.service.project.manage.ProjectDataManager.importData(ProjectDataManager.java:98)
 at com.intellij.openapi.externalSystem.service.project.manage.ProjectDataManager.importData(ProjectDataManager.java:124)
 at com.intellij.openapi.externalSystem.service.project.wizard.AbstractExternalProjectImportBuilder$1$1$1.run(AbstractExternalProjectImportBuilder.java:143)
 at com.intellij.openapi.roots.impl.ProjectRootManagerImpl.mergeRootsChangesDuring(ProjectRootManagerImpl.java:325)
 at com.intellij.openapi.externalSystem.service.project.wizard.AbstractExternalProjectImportBuilder$1$1.execute(AbstractExternalProjectImportBuilder.java:140)
 at com.intellij.openapi.externalSystem.util.DisposeAwareProjectChange.run(DisposeAwareProjectChange.java:36)
 at com.intellij.openapi.externalSystem.util.ExternalSystemApiUtil$6$1.run(ExternalSystemApiUtil.java:374)
 at com.intellij.openapi.application.impl.ApplicationImpl.runWriteAction(ApplicationImpl.java:974)
 at com.intellij.openapi.externalSystem.util.ExternalSystemApiUtil$6.run(ExternalSystemApiUtil.java:371)
 at com.intellij.util.ui.UIUtil.invokeLaterIfNeeded(UIUtil.java:2102)
 at com.intellij.openapi.externalSystem.util.ExternalSystemApiUtil.executeOnEdt(ExternalSystemApiUtil.java:391)
 at com.intellij.openapi.externalSystem.util.ExternalSystemApiUtil.executeProjectChangeAction(ExternalSystemApiUtil.java:369)
 at com.intellij.openapi.externalSystem.util.ExternalSystemApiUtil.executeProjectChangeAction(ExternalSystemApiUtil.java:365)
 at com.intellij.openapi.externalSystem.service.project.wizard.AbstractExternalProjectImportBuilder$1.run(AbstractExternalProjectImportBuilder.java:137)
 at com.intellij.ide.startup.impl.StartupManagerImpl$8.run(StartupManagerImpl.java:329)
 at com.intellij.ide.startup.impl.StartupManagerImpl.runActivity(StartupManagerImpl.java:303)
 at com.intellij.ide.startup.impl.StartupManagerImpl.access$700(StartupManagerImpl.java:51)
 at com.intellij.ide.startup.impl.StartupManagerImpl$3.run(StartupManagerImpl.java:164)
 at com.intellij.openapi.project.DumbServiceImpl.runWhenSmart(DumbServiceImpl.java:125)
 at com.intellij.ide.startup.impl.StartupManagerImpl.queueSmartModeActivity(StartupManagerImpl.java:161)
 at com.intellij.ide.startup.impl.StartupManagerImpl.access$1000(StartupManagerImpl.java:51)
 at com.intellij.ide.startup.impl.StartupManagerImpl$4.run(StartupManagerImpl.java:184)
 at com.intellij.openapi.project.DumbServiceImpl.updateFinished(DumbServiceImpl.java:246)
 at com.intellij.openapi.project.DumbServiceImpl.access$700(DumbServiceImpl.java:51)
 at com.intellij.openapi.project.DumbServiceImpl$9.run(DumbServiceImpl.java:405)
 at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:199)
 at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:715)
 at java.awt.EventQueue.access$400(EventQueue.java:82)
 at java.awt.EventQueue$2.run(EventQueue.java:676)
 at java.awt.EventQueue$2.run(EventQueue.java:674)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:86)
 at java.awt.EventQueue.dispatchEvent(EventQueue.java:685)
 at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.java:748)
 at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:577)
 at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:384)
 at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:296)
 at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211)
 at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:201)
 at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:196)
 at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:188)
 at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Caused by: java.lang.ClassNotFoundException: org.jetbrains.sbt.project.data.Play2ProjectData
 at com.intellij.util.lang.UrlClassLoader.findClass(UrlClassLoader.java:148)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
 at java.lang.Class.forName0(Native Method)
 at java.lang.Class.forName(Class.java:249)
 at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:604)
 at com.intellij.openapi.externalSystem.model.DataNode$1.resolveClass(DataNode.java:127)
 at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1591)
 at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1496)
 at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1750)
 at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
 at java.io.ObjectInputStream.readObject(ObjectInputStream.java:349)
 at com.intellij.openapi.externalSystem.model.DataNode.prepareData(DataNode.java:172)
 ... 53 more