the wallet.dll is one of the k-meleon libraries... it crashes when you try to 'remember' two sets of login info for the same site in a single k-meleon profile.
a search on 'wallet.dll' yields this:
http://kmeleonbrowser.org/forum/search.php?f=1&search=wallet.dll&globalsearch=1&match=1&date=60&fldsubject=1&fldbody=1