Mac OS 10.6.8 and Cuda 4.0.21


i got a wired problem:

I am running PP 5.5 on a macpro with nvidia quadro 4000 with the latest nvidea driver for the quatro and the latest Cuda for Mac driver 4.0
But this didn`t get Cuda working in Premiere. I checked the forum and found an answer to this problem - i needed to instal Cuda driver 4.0.21, which seems to be a beta-version.
Nevertheless i now can choose Cuda to use as GPU accelerating and everything should be fine.

But after restarting the MacPro premiere says no Cuda-Board installed and checking the driver version: it`s 4.0 again.

After reinstalling the driver 4.0.21 Cuda works again.

Does anyone have a clou or the same problem?