First off, I'd like to apologize for the fact that the crash-on-exit problem reported by various users with the 195.22 NVIDIA FreeBSD BETA release has remained unresolved for so long. Unfortunately, other work took precedence, and this problem proved too elusive to debug quickly on the side.
That said, I finally debugged this problem and can offer a band-aid until an updated BETA driver release becomes available. If you are suffering from crashes after shutting down X when using the 195.22 NVIDIA FreeBSD BETA graphics driver release, please download the attached patch and reinstall the driver following the steps below:
# tar zxf /path/to/NVIDIA-FreeBSD-x86_64-195.22.tar.gz
# cd NVIDIA-FreeBSD-x86_64-195.22
# patch -p0 < /path/to/NVIDIA_kernel-195.22-554746.diff.txt
# make clean install
The example above is for FreeBSD/amd64, but the instructions apply to FreeBSD/i386, as well.
If you're unsure if your configuration is affected, I recommend that you apply the patch.