Problem with FCKeditor in Firefox 1.5.012 on Fedora Linux

This may not be a problem with FCKeditor...

I'm using Exponent (Content Management System http://www.exponentcms.org) which uses FCK editor. On my linux workstation FCKeditor simply doesn't come up at all (screen is blank in the place where FCKeditor should normally be). I'm using Firefox 1.5.012 on Fedora Linux (Core 5). I see that FCKeditor is supposed to be working in Firefox 1.5; I'm wondering if anyone else is seeing this problem.

I'd like to update to Firefox 2.0 but Fedora has decided to not support update of Firefox to 2.0 in Fedora Core 5 - they want to simply wait for Firefox 3.0. Some people have manually installed Firefox 2.0 on Core 5 but I tried (spent many hours on it) and finally gave up.