Java crashes in Mozilla Firefox

[Per Anton Rønning]

Hi all,
I downloaded the latest Firefox, and the latest Java as well. But now FF 
     crashes when trying to start Java Plugin. My internet banking logon 
application is a good example, but it also crashes when trying to check 
if Java is correctly installed form the Java homepage (Oracle).
I Tried to go back to my previous Firefox (FF 3), but to no avail.
Has any of you encountered this problem, and managed to find a fix?
So far I am unsuccessful. I have browsed the net and found many 
references to this problem, but no clue to a fix. So I hope some of you 
guys may have something.

Regards
PA