I encountered this bug when I decided to use 'stty tostop'
on my console window. I get warning messages printed to my
console whenever I start X to the effect that fvwm wasn't
found and that it's resorting to twm to get me going. (I
have yet to care about that, since I like twm fine enough.)
It turns out that this message apparently causes xinit to
hang when starting in a console with tostop set.
I'll mail my patch to startx to turn off tostop before and
restore the original stty settings after xinit runs.
you can fix the fvwm issue by upgrading to the errata release of the
'xinitrc' package in ftp.redhat.com/pub/updates/6.0/noarch.