Can you add a terminate event to your dll? So that when you
receive the event you unload the form(s) of the main application.
Something like:

private withevents m_cDLL as MyDll

private sub m_cDLL_TerminateNow()
   dim frx as Form
   for each frx in forms
     unload frx
   next
end sub

This is much better than putting an End statement.

Marco