Can you pick "Show in directory", Shift+Right-click on an empty spot, pick "Open command prompt" / "Open PowerShell", and open (".\GMRoomPack.exe", Enter) it from there? Should tell you what the error is then.
Oh! That means that I forgot to add a DLL and you don't happen to have Neko VM installed for you to have one already.
Here's that: https://www.dropbox.com/s/02fdcssif22on30/std.ndll?dl=0
if that's all of troubles, I'll update the extension with it in a few