The shipping version of Netscape that went with RH7.2 is 4.76. That was nearly 2 years old at the time and its been a year since that release. Its a matter of a higher java standard, newer HTML, something along those lines...
I recommend getting a newer version of a browser. Netscape 6 is a kludgy beast, so you might want to try Mozilla (Netscape in development before Ted Turner and co turn it into AOL beta), Galeon, Nautilus, or my personal lightweight favorite, Opera; all of which come as RPMs.