MSI install error: This advertised application will not be installed because it might be unsafe

After spending many hours with error message's like both:

This advertised application will not be installed because it might be unsafe

AND Uninstall problems like:

the installed product does not match the installation source(s)

this worked to force the install:

msiexec.exe /i [product.msi] /qb

and this worked to uninstall the application if the process would not let me uninstall it (usually from other user's accounts (I used the 'all user's' option on the install):

MsiExec.exe /I foo.msi REINSTALLMODE=voums REINSTALL=ALL

However...

My final conclusion was that my .msi file was buried too deep inside my folders. Therefore, when I was signing on to the other users (I installed with the 'all users option') to install or uninstall, and clicked on the desktop icon, or tried the uninstall from the 'add remove programs', the installer at that point was unable to find the original .msi, again, because I had it buried too deep inside my folder.

Moving the product.msi closer to the root folder fixed all the problems.