I've been having a similiar problem for years with several different computers and hardware... and I just now fixed it. Simply have your computer use a static IP on the network, rather than using DHCP. Most routers will create a "fixed" IP address for each NIC card/computer that contacts its DHCP server the first time. Find out your IP and the DNS servers, and then input that information for your network. For w2k: network and dial up connections, right click your connection and go to properties, find Internet Protocol (TCP/IP) in the connection list, go to properties, and select "Use the following IP address" and "use the following DNS servers." Enter the local address of your computer, the subnet mask (usually 255.255.255.0), and your gateway (i.e. your router's address.. usually 192.168.x.x) This info can be found in your router config page, or by running "ipconfig -all" from the commandline.
Your net connection will disconnect for a few seconds after you make the changes, but it should still work. My router's DHCP lease is only 10 minutes, and sure enough all these errors happened in a threshold <10 mins. I don't understand why this interrupts the transfer... but hopefully this will help all of you whose please I have found while trying to solve this problem myself. My apologies if I am too wordy or explanatory to those for whom "don't use DHCP" would suffice.
-adam walling, ohio