Hi, thanks for sharing this issue.
NCrunch's MSIs are quite close to xcopy installs into the VS directory. An MSI internal error during such a process could suggest any of the following:
1. Conflict with aggressive antivirus software
2. Security settings that prevent something in windows installer from operating correctly
3. Corruption in windows installer or the O/S itself
Do you have any luck installing the product manually?
http://www.ncrunch.net/documentation/manual-installation-instructions.