Problem with 64bit Firefox and Thuderbird exiting

[David W. Florence]

Hope someone can help.
Having this recurring problem with Firefox and Thunderbird exiting when 
clicking on some URL referrals. Some sites will not display, the 
applications will exit without any errors. Examples are planetamd64.com, 
freashmeat.org and Fox News Gretawire.
Have posted a thread on the FedoraForum site, but no helpful replies. 
Searched Bugzilla, but nothing there. Have installed all the latest 
updates available, deleted profiles, did a fresh install of FC5 64bit, 
you name it, I have done it!
Any help would be appreciated.

Thanks
Dave