I just completed a text based upgrade to RH6.1 from a fully patched 6.0. The first thing that I noticed is the Netscape package version 4.7 was replaced with Cartman stock 4.61 version of Netscape.
Was the previous version the Red Hat update package? Specificaly, if you have the previous version installed, what does "rpm -q --qf '%{SERIAL}' netscape-common" say?
The above line gives the number 2 for output. The original package was the latest from the errata. I also note that e2fsprogs was upgraded prior to upgrading to 6.1. It too was downgraded in the process and required the errata upgrade.
*** This bug has been marked as a duplicate of 7263 ***