I upgraded to RH6.1 from 6.0. I'd previously updated the Netscape in 6.0 with the ver 4.7 RPMS off your web site. After completing the upgrade process with no visible problems, Netscape wouldn't run. No error message, no core file, it'd just exit after maybe a second. After lots of poking around with RPM, I found that NS-communicator 4.7 was installed, but NS-common was back at 4.6. I did an "rpm -Uvh" on netscape-common, which I still had lying around from my earlier download. All is now OK.
To clarify, no window was displayed either. Just I type "netscape", hear a bit of disk spinning and then get a command prompt back.
*** This bug has been marked as a duplicate of 7263 ***