It's unlikely to be nvidia network drivers since the problem is on a computer that's connected via a DLink WiFi dongle is it not?
I've had a problem similar, Zyxel router/modem to a computer with a Netgear W111v2 - small transfers OK, large transfers just stop. Even though signal is max the transfer rate was sub-500kB/s.
I can download the offending files wirelessly on my laptop no problem but the Desktop just stops downloading and never completes. This seems to eliminate the connection which seems rock steady and fast on the laptop.
But it doesn't eliminate the WiFi segment of the connection unless you are using the same DLink dongle for it as well.
There could be incompatibilities between the DLink dongle and the router - I would try the DLink dongle on the laptop to eliminate the WiFi segment and even then you can only eliminate it if the laptop is also running XP-SP3 so you can run the exact same driver.
Try another WiFi dongle also if you can.
Does transferring a large file over WiFi from laptop -> desktop, (and vv.), suffer the same problem?