I have Debian 3.0r1 with some parts from Debian/testing. Reinstalling Galeon didn't help. Not even removing Galeon with dpkg -P (purge, destroys Galeon's config. files) and then reinstalling. I deleted the .galeon and .mozilla directories in my homedir, and Galeon went through the "first time" questions, but kept opening windows after I had finished with them.
I have updated Galeon a couple of times, but the problem has persisted. Opening with exclusive website parameter didn't help.