I am not sure of what exactly your problems might be, but, believe me, i just downloaded the module from here:
http://dev.abducted.us/images/c/c2/Ircd_gameserv.ctested it on FreeBSD 5.5-PRERELEASE with Anope-1.7.14 (1023) and Unreal3.2.5.
I compiled the modules, and got no errors. Loaded the modules and still get no errors ... also just to note, i didn;t change anything on the code .. even a single code from that module and all the commands were working perfect and GameServ can also join/part a channel.
Also, about its user mode, the mod author(s) didn't give any modes on GameServ client, so it will not have any modes unless you gave a user modes by yourselves.