Why "Could not create a pBuffer"?

I encountered a problem when I run your code of “Medical Image Reconstuction with the FFT” from the book “GPU Gems 2”.
It says “Could not create a pBuffer” on the screen.
My card is NVIDIA Geforce 6800XT (AGP,128M/256bit).
I can’t figure out why.
And I can’t reach the authors of this chapter by using these e-mail address:Thilaka.Sumanaweera@siemens.com , donald.liu@siemens.com
Siemens Medical Solutions USA said neither of these people are currently employed with Siemens.
Could any of you help me,please?Thank you very much!
You can download the code of this chapter from http://http.download.nvidia.com/developer/…/Content/48.zip

The forum is for discussion of CUDA, which only applies to the GeForce 8xxx series of cards and later. You might try in a different forum, though I’m not sure which one. Maybe this: