Netscape Communicator 4.03 gives me error messages about problems with the colormap. One specific page that this happens on is the SmartUpdate page. I heard that upgrading XFree86 solves the problem, but when I tried to do that using RH 4.1 I ended up with a big mess. I am hoping for a simpler solution.
I'm using RedHat Linux Pro 4.1a. I also have Linux 4.1 (Vanderbilt) on-hand, but it isn't currently installed (if you have a solution that only works in Vanderbilt, I'd be willing to switch Linux versions).