People reportedly seem to have trouble with playing online, due to a PB update which causes the user to have a different version than most servers.

Updates
Starting at the 8th of November Evenbalance released first new server files that update the server to version 1.705 and one day later they updated the client files to version 2.137. It seems that the update of the client files are causing problems for players.

quote:
Saturday, 8th November 2008 [5:45PM]
Version 1.705 of the PB Server for Crysis Wars has been released to our PB Master Servers for auto-update and to our website download page. This is a maintenance release.

quote:
Sunday, 9th November 2008[3:00PM]
Version 2.137 of the PB Client for Crysis Wars has been released to our PB Master Servers for auto-update and to our website download page. This is a maintenance release.

Solution:
Click here to download the manually controlled PunkBuster Set-up which will solve the problem


To read the official post click here