server 2003 DC doesn't update WINS IP Resolution?

Hi All: I have a server2003 sp2 DC that is running DNS and has XP clients
pointing to it for name resolution.

I had made an IP change to a remote domain's website (unrelated to the
windows domain) that was picked up by DNS on the server right away, but not
in WINS, even after a week had elapsed and the DC had been rebooted several
times.

I was able to get the IP change picked up finally by running "nbtstat -R" on
the DC...but I have had reports from other people that they're experiencing
the same problem picking up the new IP of the website. I'm nervous that the
problem may be widespread, and I'm wondering what, if anything, I can do
about it, beyond telling people who eventually contact me about the problem
to tell their network admin to manually update their server?

Is this a bug in WINS or something else?