I had the same issue. You have to go into the serverstart.bat file and change that from the .1272 version to the .1277 version that is actually installed. Hope that helps.Hey everyone,
every time i wanna make a multiplayer server with hamachi and i unpack the server zip with win-rar 64bit and i wanna start the server it says:
Error: Unable to access jarfile forge 1.7.10-10.13.2.1272-universal.jar