Ok, as far as i knew this could be the problem:
Firefox use custom settings and is set to keep and save history and cockies. This way it logg this infos and other app can not access them.
As for the Testing-Statement:
Spybot have been in a long Beta but it is for every Programmer impossible to create a Program in this way, wihout the possibility there wont be a problem on the thousends of dufferent Systems into the World. Else MS would not need to update its Os after released.