Yeah... it's pretty obvious you have some sort of buggy app. Try creating a new user and see if the problem occurs on that user.
If the problem does NOT recur, then on your regular user, go to:
System Preferences > Accounts > your user account
Make a list of your login items, then remove them all. Restart and see if the problem goes away. If it does, then one of the items you removed is the culprit. If not, we can try other things.