My site, www.racetime.com, uses uddeim on every page and works great, unless you're on a Mac using FF2. It doesn't show up at all, not even in the source code. Any thoughts on how to fix it?

Little help ... ?

uddeIM does not check which os is used (except for a browser related css file when you have created seperate files e.g. for FF or Safari).

So when no output is done at all, the problem is somewhere else (never heard about that problem before).