OK for me on win2k/moz1.0RC1 and RH7.1 Moz0.7 and NS4.76 (server machine, hardly ever use for surfing). I can test on 98SE/Moz 0.9.9 tomorrow (machine is my son's and he's sleeping). Tested with and without javascript on.
I'd guess a Moz bug, myself.
As far as 98/2K there's no comparison. 2K is far better, in fact it's the only M$ OS I've used that I'm not cussing at hourly FWTW(for whatever THAT's worth). If your gonna stay on the M$ path, I'd give it a shot. Really. Otherwise, get your ass over to www.debian.org and kwitcherbitchin :)