Someone posted this in another forum as a guess as to some priority level problems. No clue if it is applicable or relevant, but I said I would pass it on:

I think the problem is related to the mshtml.dll file and the winiet.dll file
Did a search in MS Knowledgebase for both of those files and
they are known to have issues in situations where a client is used.
they even offer examples of code as to how to write to avoid problems.

Articles : Q266343 ,Q238425 ,Q315466 should offer a good start to "stabilization".