I am having troubles adding the excel reference to my project. I have already installed Primary Interop Assemblies.
The project is detecting the Microsoft.Office.Interop
I installed MS Office 13 and from then on I started getting this error in VS 2012 project. I tried adding the MS Office lib via COM control but that didnt work. Finally I had to add this library references from the "Extensions" section (not not under COM); had to select Microsoft.Office.Interop.Excel, version 15.0.0.0. That fixed the error.
Hope that helps some.