What system components else do I need to install to be able to install EN-MMDictionary Add-in?
I believe you have to install the other package listed on the official website as well. There is a Microsoft Office system Primary Interop Assemblies which I believe is the necessary one in order to have full functionality of EN-MMDictionaryAddin.
Use the following link to reach the download page from where you can acquire the mentioned package: https://code.google.com/archive/p/en-mmdictionary/downloads
