make sure ports are correctly forwarded..
make sure you have your hosts files(windows) correctly edited on server and playing machine.. as for linux.. make sure the server machine has its own hostname like with no-ip.com.. and on playing machine make sure the server machine ip is linked with the no-ip.com address for the playing machine..
and make sure youe eqem_config.xml is correct...
gimmie a little ill edit post with some snips of what to change.. (if i dont forget)
sheesh i hope some of this makes sense... kinda pulled it all out of my ass but maybe it will help hah ; )
PS: this post is also info for culex i saw on IRC.. hope he sees this maybe? /shrug