I am having the same problem.  I am using whizzywig v55i, which works fine with IE, but not with Firefox 2.0.0.14.  What is REALLY strange is that I AM able to use/acces the demos on this whizzywig site via Firefox 2.0.0.14 (i.e., javascript is obviously enabled, etc.).  There are ONLY two possibilities:
1) The culprit is v55i, which means the demos for this site are not running v55i, or
2) There is some SPECIAL configuration/setting that needs to be employed that is NOT SPECIFIED ANYWHERE in the whizzywig documentation.

Any help would be greatly appreciated, as this is obviously EXTREMELY FRUSTRATING!

I use FireFox almost exclusively for my own use, but I do test some with I.E.

Does this forum work for you with FireFox?  How about the demo?  Have you checked to make sure that JavaScript is turned on with FF.  What symptoms are you getting?

I'm using whizzywig on a few pages, and it works great, as long as it's IE.  Everything I'm reading indicates that it works on Firefox, but not for me.  Am I missing something obvious?