ArchLinux user here, completely updated, nvidia drivers 180.22-1, nvidia 8800GTS 512 card.

I've tried both the sdl and glx versions, and the error is consistent - nexuiz starts normally, it doesn't appear to use the mouse - the cursor remains in the starting position. After quitting nexuiz (using tab to navigate to the quit menu), the mouse cursor will move around my desktop, but can't click anything, and moving the mouse around doesn't even change window focus (which is default behaviour in awesome WM). Likewise, I am unable to use keyboard shortcuts to restart X or ctrl+alt+Fkey to switch to a virtual terminal, so the only thing I can do is reboot the PC.

Has anyone else encountered this error or does anyone habe the slightest idea as to what could be wrong?

EDIT: I should note, I've tried both downloading it from your site, and installing the version in the arch community repos (which is version 2.4.2-1).

PS, apologies for my english.

How is your mouse configured in xorg.conf?

Hmm, never heared about such problem. However evdev is known to give problems. In case you use that try an other mouse driver (or try the beta release of the next version thats current up for testing, it has some improvements in that area)