what is your Ubuntu version?
Oh, i forgot to write os versin <facepalm>
this looks like driver installation error. is OpenGL acceleration working? what print fglrxinfo?
I agree with nou, it seems the AMD kernel module did not load correctly.
call: lsmod | grep fglrx .
If you can't find the fglrx in the module list, it means the kernel mode driver did not load.
If you install the AMD driver package from the AMD web site be sure you have the following packages already installed. The packages are installed by calling: sudo apt-get install <package name> .