Unexpected PsiInvalidElementAccessException on psiClass.getSuperTypes() Follow

I'm getting exception during invication of psiClass.getSuperTypes()...and have no idea what is wrong
IntelliJ IDEA 8.1.3#9886 built at 17/06/2009

Error message: Element: class com.intellij.psi.impl.source.PsiClassImpl: Element: class com.intellij.psi.impl.source.PsiClassImpl
com.intellij.psi.PsiInvalidElementAccessException: Element: class com.intellij.psi.impl.source.PsiClassImpl
       at com.intellij.extapi.psi.PsiElementBase.getContainingFile(PsiElementBase.java:10)
       at com.intellij.extapi.psi.StubBasedPsiElementBase.getContainingFile(StubBasedPsiElementBase.java:54)
       at com.intellij.extapi.psi.PsiElementBase.getContainingFile(PsiElementBase.java:58)
       at com.intellij.extapi.psi.StubBasedPsiElementBase.getContainingFile(StubBasedPsiElementBase.java:54)
       at com.intellij.extapi.psi.PsiElementBase.getContainingFile(PsiElementBase.java:58)
       at com.intellij.extapi.psi.StubBasedPsiElementBase.getContainingFile(StubBasedPsiElementBase.java:54)
       at com.intellij.extapi.psi.StubBasedPsiElementBase.getProject(StubBasedPsiElementBase.java:51)
       at com.intellij.psi.impl.source.PsiReferenceListImpl.getReferencedTypes(PsiReferenceListImpl.java:12)
       at com.intellij.psi.impl.PsiClassImplUtil.getExtendsListTypes(PsiClassImplUtil.java:374)
       at com.intellij.psi.impl.source.PsiClassImpl.getExtendsListTypes(PsiClassImpl.java:30)
       at com.intellij.psi.impl.PsiClassImplUtil.getSuperTypes(PsiClassImplUtil.java:420)
       at com.intellij.psi.impl.source.PsiClassImpl.getSuperTypes(PsiClassImpl.java:100)
       at com.uwiss.jenive.idea.inspection.swtjface.WidgetNamingConventionInspection.findFqdnFromClass(WidgetNamingConventionInspection.java:149)
       at com.uwiss.jenive.idea.inspection.swtjface.WidgetNamingConventionInspection.process(WidgetNamingConventionInspection.java:129)
       at com.uwiss.jenive.idea.inspection.swtjface.WidgetNamingConventionInspection.access$000(WidgetNamingConventionInspection.java:43)
       at com.uwiss.jenive.idea.inspection.swtjface.WidgetNamingConventionInspection$1.visitField(WidgetNamingConventionInspection.java:106)
       at com.intellij.psi.impl.source.PsiFieldImpl.accept(PsiFieldImpl.java:101)
       at com.intellij.psi.impl.source.JavaStubPsiElement.acceptChildren(JavaStubPsiElement.java:74)
       at com.intellij.psi.JavaRecursiveElementVisitor.visitElement(JavaRecursiveElementVisitor.java:40)
       at com.intellij.psi.JavaElementVisitor.visitClass(JavaElementVisitor.java:59)
       at com.intellij.psi.impl.source.PsiClassImpl.accept(PsiClassImpl.java:201)
       at com.uwiss.jenive.idea.inspection.swtjface.WidgetNamingConventionInspection.analyzeCode(WidgetNamingConventionInspection.java:96)
       at com.uwiss.jenive.idea.inspection.swtjface.WidgetNamingConventionInspection.checkClass(WidgetNamingConventionInspection.java:80)
       at com.intellij.codeInspection.BaseJavaLocalInspectionTool$1.visitClass(BaseJavaLocalInspectionTool.java:97)
       at com.intellij.psi.impl.source.PsiClassImpl.accept(PsiClassImpl.java:201)
       at com.intellij.codeInsight.daemon.impl.LocalInspectionsPass$1$1.run(LocalInspectionsPass.java:7)
       at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:13)
       at com.intellij.codeInsight.daemon.impl.LocalInspectionsPass$1.process(LocalInspectionsPass.java:2)
       at com.intellij.codeInsight.daemon.impl.LocalInspectionsPass$1.process(LocalInspectionsPass.java:1)
       at com.intellij.concurrency.JobUtil$1.run(JobUtil.java:44)
       at java.util.concurrent.Executors$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:619)