Version:           4.7.3 (using KDE 4.7.3) 
OS:                Linux

Hardware: Nvidia 6800 GS

Previously in KDE 4.6 and below, I was able to activate desktop cylinder/sphere. Now it appears that I can't, while desktop cube works as expected. 

a tail of .xsession-errors states:
kwin(1400): Shaders are not supported 
kwin(1400): The cylinder shader failed to load! 

kwin(1400): Sorry shaders are not available - cannot activate Cylinder 

My card supports shaders, could be a driver or detection issue? If shaders are not available, these options probably shouldn't be selectable with the error hidden in .xsession-errors anyhow, but my card definitely supports OpenGL v2.0 shaders.

Reproducible: Always

Steps to Reproduce:
Go to System Settings | Desktop Effects | All Effects
Go to Desktop Cube | Configure
Assign a control for Desktop Cube or Desktop Sphere (I used Ctrl+F11, and tested both)
Activate the control
When failed, run 'tail ~/.xsession-errors' and read the output.

Actual Results:  
Errors were written to .xsession-errors, but no visual cue or error message was given.

Expected Results:  
The desktop cylinder/sphere should be activated.