Rawhide Firefox problem

[Alan]

I have been having a problem with the version of Firefox for a couple of
days now.

When I try and start it it spins for a bit and then nothing happens.

If I start it at a command prompt, I get the following:

Error: Platform version '1.9b4pre' is not compatible with
minVersion >= 1.9b5pre
maxVersion <= 1.9b5pre

I have looked in bugzilla and searched Google to find something useful. 
Nothing so far.

Any clue what is wrong here?  I have tried renaming ~/.mozilla and
removing old library paths.  Nothing seems to work.

Ideas?