Can’t map drives on Wireless connected machines

I have a problem with 2 NEC desktop PCs which use a peer to peer wireless connection. Each PC had the other’s C drive mapped over the wireless connection & worked fine but now neither will connect to the other, just get “An error occurred reconnecting. The local device name is already in use”. Both machines show a good connection to the peer to peer wireless network but if I try to map the drives again I get “The network path could not be found”. Any ideas?