CUDA initialize failure Mathematica fails to initialize CUDA

I am afraid my ask for help might be very primitive to the experts in this forum. I uses Mathematica 8 on MacBook Air w/t OSX Lion.
I downloaded CUDA driver 4.0.50 and CUDA resources and they works fine. But once power-off Mac and later power-on,
CUDA cannot be activated w/t message “CUDA failed to initialize”. Finally found that reinstall of Driver fix this. But each time
power-off and on Mac, same problem occurs and I must reinstall Driver. I have another combination of Mathematica 8 on
MacBook Pro w/t Snow Leopard and exactly the same problem occurs on this combination. I have checked that both Driver and
Resources are properly installed where they should be. I assume problem is caused by something improper between
Mathematica and CUDA, not by Mac, but don’t know further. Your advise will be highly appreciated.

About your MBP with Snow Leopard installation, you have to switch on the proper graphic card in order to use Cuda, you can make it from system preference,

or use something like this: Cuda will not work if you are using the integrated graphic chipset. I don’t know about MacBook Air, don’t know how it could work with Cuda without having a graphic card. Hope this helps. Ciao

Thanks for your reply to my “Ask for Help”. I found that I misunderstood nature of my problem. All the files etc for CUDA driver and or Resources
are confirmed to be properly installed where they should be. But CUDA.kext is unable to be loaded at each boot time. I posted this in this FORUM
as “Is there any good way to load CUDA.kext at boot”. I appreciate if you refer that post and advise me further. Sorry for bother you due to my
insufficient understanding. Thank you very much for your response.