There are a few solutions to this problem.
1. Crossfire servers were down or having maintenance at this time, Please check server status here;
http://www.mpgh.net/forum/243-crossf...er-status.html
2. Many many people who get this error (including myself) simply re-try a few times and it ends up working! Recommended that you try a few times each hour or so. It could be that at that time there was a heavy server load - or something to that effect.
3. If you are using Vista/Windows 7 - Make sure to run Crossfire as Administrator. In addition, Be sure to try different "Compatibilities".
Right Click - Properties - Compatibilities - Windows XP
4. Z8games [MOD]GreyCloak;
"If you are unable to patch the client, download the newest installer (v1051) from the download page. That will solve the problem. "
People highly recommend you try from an Alternative site that is not Z8games;
If you are unable to patch the client, download the newest installer (v1051) from the download page. That will solve the problem.
Hope something works for you!