You Were Never Here!
Quake 3 Beginners Guide
Network Protocols
Worth mentioning first and foremost, this is the main problem issue for newcomers. Several game updates or ‘point releases’ were issued over the life of Quake III, each one with a new network protocol. A protocol is the "language" in which the server communicates with the client. If the server uses a different protocol than your client game, you cannot to connect to that server since the server and client don't understand each other. Mismatched clients are dumped back to the menu with the message "server uses protocol xx" where xx is the protocol number.
Quake III uses different network protocols depending on the point release used.
Point release->Protocol:
1.16 -> 43
1.17 -> 45
1.2x -> 48
1.30 -> 66
1.31 -> 67
1.32c -> 68 ( the release info in this guide with regards to punkbuster)
1.32e-> 68 (the latest point release)
See the Quick Start Page for links to the latest point release. Only the latest point release is necessary and already contains updates from all previous releases.
"User Interface is version 4, expected 3"
This means your quake3.exe isn't compatible with the currently installed point release. Reinstall the 1.32 PR; if that does not work the only solution is to move all of the .pk3 files located in baseq3 except for pak0.pk3 to a seperate and new location and then reinstall the latest point release. After doing that, move the .pk3 files back into your baseq3 folder.