Collection modified error

Occasionally, i get an error indicating "Collection was modified after the enumerator was instantiated.", upon typing a "." after an object reference. So, I am guessing it has to do with intellisense. But, it is difficult to diagnose because as i mentioned... it doesn't happen all the time. But, when it does happen the editor (form that contains the editor in my app) closes. Any ideas? (Also, note I recently upgraded to build 282 from build 281... but I had this same problem with 281, so i don't think it is specific to 282).

Here's the StackTrace:
at System.Collections.Specialized.ListDictionary.NodeKeyValueCollection.NodeKeyValueEnumerator.MoveNext()
at d.w()
at ActiproSoftware.SyntaxEditor.Addons.DotNet.Dom.DotNetProjectResolver.a(IDomType A_0, String A_1)
at ActiproSoftware.SyntaxEditor.Addons.DotNet.Dom.DotNetProjectResolver.GetTypeInheritanceHierarchy(IDomType type)
at ActiproSoftware.SyntaxEditor.Addons.DotNet.Dom.DotNetProjectResolver.GetStandardModules(IDomType contextType, String namespaceName, DomBindingFlags flags)
at ActiproSoftware.SyntaxEditor.Addons.VB.VBContext.a(DotNetProjectResolver A_0, String A_1)
at ActiproSoftware.SyntaxEditor.Addons.VB.VBContext.ResolveForCode(Document document, CompilationUnit compilationUnit, DotNetProjectResolver projectResolver)
at ActiproSoftware.SyntaxEditor.Addons.VB.VBContext.GetContextBeforeOffset(Document document, Int32 offset, CompilationUnit compilationUnit, DotNetProjectResolver projectResolver, Boolean forParameterInfo)
at ActiproSoftware.SyntaxEditor.Addons.VB.VBSyntaxLanguage.GetContext(SyntaxEditor syntaxEditor, Int32 offset, Boolean beforeOffset, Boolean forParameterInfo)
at ActiproSoftware.SyntaxEditor.Addons.DotNet.Dom.DotNetSyntaxLanguage.b(DotNetLanguage A_0, SyntaxEditor A_1, Boolean A_2)
at ActiproSoftware.SyntaxEditor.Addons.VB.VBSyntaxLanguage.ShowIntelliPromptMemberList(SyntaxEditor syntaxEditor)
at ActiproSoftware.SyntaxEditor.Addons.VB.VBSyntaxLanguage.OnSyntaxEditorKeyTyped(SyntaxEditor syntaxEditor, KeyTypedEventArgs e)
at ActiproSoftware.SyntaxEditor.SyntaxEditor.a(EditorView A_0, Keys A_1, Char A_2, Boolean A_3)
at ActiproSoftware.SyntaxEditor.SyntaxEditor.OnKeyPress(KeyPressEventArgs e)