Hi Stefan,
your name doesn't sound as if you were English or American, but maybe you aren't German either. ;-)
I am Austrian actually. You came very close ;-)
What the heck is a backslah good for in a URL path?
IE has a built-in pseudo intelligence that transforms backslashes to regular forward slashes before the URL is submitted to the server. Firefox, however, does not do such a translation, an so the server tries to locate files with backslashes in their names.
The backslashes caused the problem. I Changed them to forward slashes and now it's working fine now. Thank you very much!
Best regards,
Stefan