I think I know what his real problem is, but unfortunately not the exact cause. This discussion might go better under troubleshooting at this point, but here goes:
Not too long ago I had the same problem with trem.tjw.org: You join the sever and click to get the menu to join a team. But instead of being presented with the menu, you get an error about the build timer. While doing /team aliens worked, the game was still unplayable because of other random errors popping up. The human side did have some other errror message that was completely out of context as well.
However, I joined trem.tjw.org yesterday and all was fine. So my completely unfounded guess would be that either something went wrong backporting the server which is now corrected, or there was something weird happening on my end which just so happened to rectify itself without my changing anything - or something else entirely.
Just thought I'd post this to hopefully clarify the OP's issue. Maybe it would help if he specified where he got his server from and if it also happens with the stock server (which I doubt).