You don't have the correct OpenGL-providing video drivers for your card installed. If you do have an ATI card as your signature suggests, head on over to www.ati.com
and download the latest driver and follow the instructions. If you run into trouble, fret not, there are probably a thousand of threads here dealing with installation of these drivers.
The language.cfg error and other configuration errors are OK, at least not lethal, and should only be temporary once you have saved your settings (if I recall correctly).
One word of warning though: Don't ever run programs as root unless you have to, especially not games. Running as root means increased security issues by the power of ten. I had a special user set up on my gaming server to run Enemy Territory and it worked wonderfully, but you should use your usual user account if you don't run a server.