firefox internal error

[Christoph Wickert]

I was trying to start firefox while my system was under heavy load from
spamassassin filtering todays mail.

$ firefox
$ INTERNAL ERROR on Browser End: Expected a version > 5! Version = 4
System error?:: Permission denied

or 
System error?:: Success

No firebird, the error remains, only moving my ~/.phoenix folder helped.
Anybody else experienced this?

$ rpm -q firefox
firefox-0.8-1.rhfc1.dag

Christoph