Networking issues - cant copy files

[pkroks]

i dont know whats wrong with my network. i am connected to a LAN at home with about 5 other computers. we go through a router for internet access. but i have been trying to transfer files from one of the machines to a new one we just got. every few minutes or so the network seems to restart or refresh itself because whilst i am copying, after about 5mins or so it will say that the network address is not found. i go to the computer concerned and its working fine. i can ping both ways but cant copy files. does it have something to do with the fact that i am running windows xp pro with sp1 and 2 on the one machine and windows xp home with sp1 and sp2 or the other?