When trying to install a VS2015 console app onto one of my servers, I get this error:
http://imgur.com
Problem solved.
First I tried the answer from Nino and gacutil.exe is not installed on that server, so I could not run that cmd.
After going through the project in Visual Studio 2015 properties/Publish settings, under Install Mode and settings, click button "Application Files..." and make sure that dll file is "included" in publishing. The dll i needed was not included, but after including it, re-published, everything installed just fine.