NET Add-in Not. A runtime error occurred during the loading Windows 8

I have created a MS Project Addin that works on my target machine (running Windows 7) and other PC running Windows 7.

I then tried to install the same Addin on another machine running Windows 8 which then gave me the"Load Behavior. Not Loaded. A runtime error occurred during the loading of the COM Add-in".

Both machines are running MS Office 2013 and MS Project 2013.

I have reviewed other threads, but haven't seen any issues related to Windows 8.

Any thoughts?