FYI:
Upon installing 64 bit firefox on RHEL 5/Centos5/SAL5 , the first problem everyone seems to complain about is no working java plugin. A patched plugin from the <discontinued> Blackdown Project was available, but it was written against the vulnerable JRE 1.4.2.
I too gave up on this until I discovered Red Hat's "iced tea" project. The latest incantation for Fedora Core 8 loaded well on a RHEL5 box using rpm's:
java-1.7.0-icedtea-1.7.0.0-0.19.b21.snapshot.fc8.x86_64.rpm java-1.7.0-icedtea-plugin-1.7.0.0-0.19.b21.snapshot.fc8.x86_64.rpm tzdata-java-2007h-1.fc8.noarch.rpm
Then do:
alternatives --config java and select the new 1.7 JRE.
Usually FC8 stuff doesn't install well on RHEL5/Centos5/SAL5 boxes. However, these worked like a charm SO FAR. [ Note, if you try these, uninstall all of your firefox extensions first because some of them have the potential to create the infamous XBL error message for non-root users]. After installation, navigate to Sun's java site and test using their applets to make sure you installed correctly.
YMMV. May cause loss of some functionality elsewhere in the system. If you browse for more then four continuous hours you may have contracted site fixation disease, contact your physician at once.
regards,
benm