firefox hangs second time it's run

[Chris Shenton]

I was running 6.2-PRERELEASE (?) happily until a couple days ago when
I cvsupped to get 6.2-RELEASE, actually 6.2-STABLE.  Now when I start
firefox it works -- the first time.  If I stop it, then start again,
it never materializes on the screen.  Logging out, killing XDM doesn't
help; a reboot it required (and I have to remove it's lock and
.parentlock files)

"top" has shown it in STATE "kserel" burning very little CPU.  "ps" shows:

  chris at Bacalao:bin<112> ps -axw|grep fire
   1739  ??  I      0:00.00 /bin/sh -c firefox
   1740  ??  I      0:00.00 /bin/sh /usr/local/bin/firefox
   1744  ??  I      0:00.00 /bin/sh /usr/local/lib/firefox/run-mozilla.sh /usr/local/lib/firefox/firefox-bin
   1748  ??  S      0:02.30 /usr/local/lib/firefox/firefox-bin

I can try and kill -9 it, but it just sits there, as top says:

  PID USERNAME    THR PRI NICE   SIZE    RES STATE    TIME   WCPU COMMAND
 1748 chris         3  96    0 66408K 42528K STOP     0:02  0.00% firefox-bin

but it never dies.  

Any ideas?

I'm using portupgrade to make sure all my dependencies are up to
date.  Anything else I should look for? 

Thanks.