I think is a limit of the version that you are using NAV 2013, it should work only using NAV 2013 R2
"Add-ins that are developed with Microsoft Dynamics NAV 2013 are still supported and displayed on a Microsoft Dynamics NAV Windows client only. Using that framework you can continue to write add-ins for the Microsoft Dynamics NAV Windows client. Using the new framework in Microsoft Dynamics NAV 2013 R2, you can write add-ins that can be run from any client."