If you baught it you should have the key. Also we don't have the UT99 for download on this site anylonger, so you didn't download it from us. If for some reason you don't want to use the key that should have came with the one you baught then you need the nodelta436 patch

You should beable to find it here.
http://www.3dgamers.com/games/unrealtourn/downloads/