Installing games under Vista

I have been trying to install the game Urban Terror under Vista but I keep
getting the following error message Can anyone help?

GLW_StartOpenGL() - could not load OpenGL subsystem

I have updated the video drivers, from ATI's website, and I think thats
where the problem lies I have run the driver update as administrator and it
goes thru the throws of updating but nothing seems to have changed after the
"update" I am still left with the same old drivers after a restart as I had
before the "update".
What am I doing wrong?

Adrian