TRIMBLEIN is not an AutoCAD 2016 command. It's not a CADmep 2016 command either. 

As I said earlier, if that works in your install of 2016, it's another software package or macro or lisp routine or alias or something that someone else created. 

I'd check in the "draw..." folder listed in your screen cap because CADmep out of the box does not have any folders with that name under "C:\Program Files\Autodesk\Fabrication 2016\CADmep\"