i don't know if that is important to u too, or if all of the probs are gone, but mine was solved now for the version, i've bought through Steam.
I tried all of the solutions the forums provided me, like adding dashes, or replace the variable "%cdkey%" with the key (even with a Key from my DVD-Version)
and nothing worked out for me. I couldn't login to the MWLL-Servers, because like u all, i got the error with "Server Authentification failed (3)" again and again.
But the last thing i did, solved my problem. The Solution is so easy. After now 4 days, since i bought my Crysis, i lost my patience, because of the issue.
And then cames the idea to erase the hole thing and to forget it. Lucky me, i told myself to give a last try by reinstalling from steam again.
So i deleted my Crysis folders and downloaded Crysis Wars again. These time i played it for one time by logging into a server and played for one time,
then i quited the game and started the installation of the MWLL. After all Updates were done, i was able to start and to logging into the Games w/o issue.
There was no need to contact EA for a new CD-Key or anything else. I Think that is somewhere in the hole system a log which is wrongly interpreted.