Yeah this game is worth it
Sounds like a Gamespy/CD Key registration error.
Make sure you have a profile setup in Crysis Wars and that you have joined a game in Crysis Wars without loading the MW:LL mod first. You don't have to play the game, but you do have to join one and let it load first. The first time you load a level in Crysis Wars Multiplayer it sets up your profile information and registers your game's key with your Gamespy account.
After than you can exit Crysis Wars and load MW:LL using the MWLL Launcher program that came with the mod. That should clear the error you've been having, but let us know if not.
