No Class Def found and other issues I get with my own plugin in 8.2

Hi, 

I am getting the same error for my own plugin as these are: http://statistics.netbeans.org/exceptions/detail.do?id=215797. 33 duplicates. How do I know if it has been fixed?

Here is what I get when doing an autocomplete:
===========
SEVERE [org.openide.util.RequestProcessor]: Error in RequestProcessor org.netbeans.spi.editor.completion.support.AsyncCompletionTask
java.lang.NoClassDefFoundError: com/forcenb/editor/vf/completion/VfCompleter
    at com.forcenb.editor.vf.completion.vfCompletionProvider$1.query(VfCompletionProvider.java:51)
    at org.netbeans.spi.editor.completion.support.AsyncCompletionTask.run(AsyncCompletionTask.java:223)
===========

Another issue is that I get strange error:
java.lang.ClassCastException: com.forcenb.project.ForceProject cannot be cast to com.forcenb.project.ForceProject

in a code like this:

                    FileObject file = Utilities.actionsGlobalContext().lookup(FileObject.class);
                    ForceProject project = null;
                    if (file != null) {
                        project = (ForceProject) FileOwnerQuery.getOwner(file);
                    }

Any clue why would this be happening?

Thanks.