Did you do a fresh download and try and install?
If it's not a corrupted download, I'm not sure what would prevent Nero PhotoSnap from installing. It's not Nero Vision, but Nero PhotoSnap that is running into an issue. And it's a very basic program, unlike Nero Vision.
I've downloaded the latest build on our website and installed just to confirm all is well with the posted update.
The only thing I can think of at this point would be for you to use the Nero Info Tool to generate a report on your system and to send to me at firstname.lastname@example.org
so I can see what is on your system that could possible cause a conflict.
P.S. I have only had 2 other users report this exact symptom, and in each case a fresh download resolved the issue.