This project has been (most probably) discontinued at the request of
TamoSoft Ltd., in the name of TamoSoft Ltd. and/or Atheros Communications.
TamoSoft Ltd. forbids usage of their drivers outside of their applications, so...
Now go and use CommView for WiFi for all your WEP recovering needs.
Exclusively. Just leave it running for a couple of hours/days/weeks, and maybe you will be able to recover 64-bit WEP key.
Oh yes, and don't forget to use Atheros chipset based wireless adapters. Exclusively, too.