I'll give a better explanation as to what the code is doing.
The server portion is a linux based app that uses the pcap library to read in a pcap dump file(from airodump-ng for example) and look for the different access points and the data from them. It then looks for which ones are WEP and displays those for the user to choose which one to attempt cracking.
It then loads up the IV and the DATA from the packet and waits for a client to connect.
The client connects, receives the IV, what portion of the wep key to try, as well as the DATA section of the packet. It then runs RC4 on the data packet with the key, checks to see if the CRC is correct. If it is it sends the key back to the server for it to check the rest of the collected packets to make sure it is not a false positive. If it is not correct, it continues on cracking.
Therefore it is possible to have a client run under windows,linux,etc. because it does not rely on libpcap, it just needs to be able to do RC4.
So really its just a big distributed system for cracking 64bit wep keys.
Hopefully that explains things better.
-Berger