hi had to sign up just to respond to this,.
the problem your having is with windows not the router.
how do i know this?
well i have a similar problem
basically i was using a cut down version of windows with some stuff removed and never got the problem
then iwent to vista and now back to an up to date xp sp2 oct edition and the problem happens on both.
i dont know what settings it is but its to do with the way windows connects to wireless connections - nothing to do with your router!