DOUBLE POST FOR THE WIN!!!!!!!!!
Ok from what I can gather this is caused by your machine using the default client port [i.e. 27005] already, which seems to be common in Windows XP. I am unable to duplicate this error in 2k. 2k throws WSAEADDRINUSE if the port is in use, so I'm not sure that is the problem.
My guesses are as follows:
1). Bad Winsock dll
2). Bad TCP/IP stack
3). Conflicting Ports
4). Firewall
5). VIA KT133A motherboard chipset w/o proper 4-in-1 patch
6). Windows 2k w/o service pack 2
7). Punkbuster conflict
My probable solutions:
1). Bad Winsock dll:
Contact Microsoft Technical Support for step-by-step instructions on how to reinstall Winsock for your operating system.
2). Bad TCP/IP stack:
Remove all TCP/IP instances from Network Properties. Goto Control Panel-> Add/Remove Programs-> Windows Setup and remove all of the Communications components. Restart then repeat the same procedure, but instead check the box and install the components. Next readd TCP/IP in your network properties.
3). Conflicting Ports:
Try adding this to the end of your command line:
+clientport 27055
4). Firewall:
Disable ZoneAlarm. If you run BlackICE setup an allow set for ports 27005 thru 27030. If you have Windows XP disable the internal firewall, or if you use ICS disable that.
5). VIA KT133A motherboard chipset w/o proper 4-in-1 patch:
Visit
www.via.com and get the latest 4-in-1 patch.
6). Windows 2k w/o service pack 2
Read the following Microsoft Knowledge Base article here.
7). Punkbuster conflict:
Disable the PunkBuster client on your machine and try non-PunkBuster servers.
Taken from: http://cs.helpandsupport.net/?aid=37