I think this is the one I submitted anonymously http://youtrack.jetbrains.com/issue/DOTP-5196
The main problem is the form just won't go away unless I use task manager to kill it - which I have to do every time I use DotPeek starting from a couple of days ago. No idea why it's just started, since I have been using the same version for some time.
Exception Submitter should close after exceptions are submitted; please try to verify that you have no pending exceptions. Also, submitting as registered user should help as well.
Also, note that release version won't bother you with the exceptions; so it is kind of a temporary issue before dotPeek 1.1. release.