1. You should read bios of your LAN cards. Then try to set-up them in that same way (especially LAN speed). In some cases you have to set-up properities in your OS'es.
 
2. Just try to forbid sleep mode in LAN card driver - or - recognize how long is your cable. If it's longer than 100 m then sometimes you can have got problems.

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

You can go the static IP route, but with XP its not a must (BUT, if you use either of these you have to do the same on both PC's, you cant do static on one and AUTO on the other), the 2 PC's will do everything automatically, the one thing you need to check is that both PC's are set to automatic or forced 100mb, you cant have one on auto and the other forced to a 100mb, even though it shows you that they are both connected at a 100mb it will be dog slow.
Go to you local area network properties, unders the general TAB click the CONFIGURE button, Click the Advanced TAB, look in the list of stuff, there should be something like "Link speed & Duplex", click on it, then to the right of that you have a dropdown menu, select auto. Do this with both PC's, restart both and try to copy something.
If you still have a problem then there is something wrong with your network cable, try another one.
 
Wicked