Changing login and gameserver to local ip does not work

I tried everything, i know my way around and i can confirm that just changing the localhost (127.0.0.1) to an internal ip address does not work.
The client will display an error telling you the gameclient files are corrupt and you need to repair or redownload and such.

Changing everything back to localhost (127.0.01) makes everything work instantly again.

I also fixed any loopback issues thru host file to see if that was the case, but it just wont work with anything else then 127.0.0.1

Someone has this server working on outside ip addres? And maybe could tell us what goes wrong? Or what i am doing wrong?

I did change the correct files in login and gameserver, and the correct entries.

check out kipstyle reply on ERROR The file is corrupted. If it persists, please................ thread. it helps me.