sage.mozdev.org crashes Firefox with and without browser safe mode

Howdy

I'm running FF on Slackware 9.1

FF has been segfaulting and crashing on me all the time.  Here's the 
feedback I get when I start FF from an xterm in safe-mode and then try 
to visit sage.mozdev.org:

  joe@zara:~$ firefox -safe-mode
*** loading the extensions datasource
*** loading the extensions datasource
/usr/local/firefox/run-mozilla.sh: line 451:  6024 Segmentation fault 
    "$prog" ${1+"$@"}
joe@zara:~$

I updated my JRE, which badly needed doing anyway, to see if that had 
anything to do with it and it did not.