Change cg profile

I use shadow sample from panda3d samples.

Then I add these lines of code to advance shadow python file:

loadPrcFileData("", "basic-shaders-only #f")
loadPrcFileData("", "notify-level-glgsg debug")

these for cg file:

//Cg profile glslv glslf  

void vshader(float4 vtx_pos....

and the result of console is:

Cg vertex profile = arbvp1  id = 6150
Cg pixel profile = arbfp1  id = 7000

How to change cg profile ?
How to know that cg profile is avaiable or not ?

After change driver to NVIDIA driver (not open source driver like before - default on ubuntu)

It works!