For direct access use https://forums.oldunreal.com
It's been quite a while since oldunreal had an overhaul, but we are moving to another server which require some updates and changes. The biggest change is the migration of our old reliable YaBB forum to phpBB. This system expects you to login with your username and old password known from YaBB.
If you experience any problems there is also the usual "password forgotten" function. Don't forget to clear your browser cache!
If you have any further concerns feel free to contact me: Smirftsch@oldunreal.com
If you have the UT:GOTY edition of the game, you probably found out that you can install ChaosUT from there. But it is not recommended - the ChaosUT version there is very, very old, and it's only half of the ChaosUT goodness. And it will probably cause version mismatches with ChaosUT servers, if any. So, to make sure you have the latest ChaosUT, don't install it from the UT Bonus CD, instead, get it here: http://chaotic.beyondunreal.com/c_download.php?view=cut
And install it when you download it. If you happen to have the old version installed already, you can overwrite the old version with the new installer.
Found out why the ChaosUT weapons are more detailed in the UT GOTY CD: they simply use S3TC textures instead of the usual ones. Simply replacing the textures will be enough to make them the same detail or even better.