[K12OSN] Firefox core dumps - CentOS 6

[Phydeaux]

We've moved our LTSP installation from Fedora 13 to CentOS 6 over the summer
and school is set to start Monday.  All seemed well, but then we fired up
Firefox.  After starting and displaying a window (sometimes it even renders
the window) it core dumps with a bus error as follows:

   /usr/lib64/firefox-3.6/run-mozilla.sh: line 131: 32095 Bus error (core dumped)
"$prog" ${1+"$@"}

We tried installing Google Chrome, but it too fails to load, displaying this:

   /opt/google/chrome/chrome: /lib64/libz.so.1: no version information available
(required by /opt/google/chrome/chrome)
   [31429:31429:606701736390:ERROR:browser_main.cc(970)] GLib-GObject:
gsignal.c:2270: signal `preedit-changed' is invalid for instance `0x578fe30'
   Bus error (core dumped)

We've got a plain-vanilla CentOS installation.  I tried removing the .mozilla
directory to allow it to start from scratch.  I tried both with and without
the Flash plugin installed.  I've gotten nowhere.  Based on research and
reports of similar problems I found I have reinstalled xulrunner, JRE, Firefox,
Chrome, and probably a few other packages

School starts Monday.  Does anyone have any clues as to what might be wrong?

reb