I am getting this message in a stateless form.  In the old version of Creator errors would show something meaningful info, like a brief description and a line number.  In the new version this seems to be all I get.  I looked under Settings - > Developer Tools -> Logs but nothing is listed.  Is there somewhere else I should be looking.  Is there any other way to get detail on this error statement.  If your onclick script is of any significant size it is essentially impossible to troubleshoot this sort of error.