Problem in installing radeon driver

[Superymk]

Hi all,

My question is quite basic but I didn't find any kind of -user mailing 
list. Sorry for bothering.

I get a problem when installing radeon driver in my box. The 
configuration is: i7 965, Intel DX58SO, PowerColor HD 6750, Ubuntu 11.04 
x64.

I try to follow the steps in 
http://www.x.org/wiki/radeonBuildHowTo#Mesa3D. I firstly try to remove 
fglrx packages. Here is my steps:

delete all the files in /lib/modules/fglrx,
depmod -a
apt-get install --reinstall libgl1-mesa-glx libgl1-mesa-dri
Restart x

Then I run LIBGL_DEBUG=verbose glxinfo. The output is that:

name of display: :0.0
libGL: OpenDriver: trying /opt/xorg/lib/dri//tls/swrast_dri.so
libGL: OpenDriver: trying /opt/xorg/lib/dri//swrast_dri.so
Error: couldn't find RGB GLX visual or fbconfig

Does this mean my card cannot be supported by radeon driver at current? 
I want to print customized information when handling OpenGL commands in 
the lib.

Thanks!
Superymk