what about this?
i have two computers. comp A and comp B
the comp A is on the router, and the comp B is on wireless network. and comp B trying to send file through MSN to an external computer (some where else), but it can't..
the comp B is unable to send File to an external comp but it can send to Comp A. however at the same time comp A can't send any files to comp B, but at the same time, the external computer(somewhere else) can send file to the comp B
so comp B is able to send file only to
comp A. and the external computer can send files to both comp. and comp A can send file to only external comp.
what the hell is going on here?
is it becuase of the network address translation advice (NAT) , wireless connection or is it because of the IP address???
help please.....

I think your problem is that the ports used for file transfer in msn are blocked by default on your router. What u can do, is open the configuration panel of your router and there add the computer b to the computers who have access to the DMZ (Demilitarized zone) This means that u ll have a direct connection to the net without any port restriction. THe second solution is to configure your router so it allows the msn file transfer port to be open and used.

I ll try to find the port that msn uses and post it later here.