You don't get firefox on an upgrade from RHEL 3 to RHEL 4.
Committed code to CVS to fix this. Should bring in firefox on an upgrade if you have mozilla or netscape installed previously.
Mass-closing lots of old bugs which are in MODIFIED (and thus presumed to be fixed). If any of these are still a problem, please reopen or file a new bug against the release which they're occurring in so they can be properly tracked.