Both.

Check your MoI ini file to see if it has an executable path in it and if it pointing at the installation you are using...

Also, I think I remember the customUI comes with some of the commands "preconfigured" with some of the scripts/commands, and included that underscore.... It's been awhile, so I don't remember off the top of my head, and I am not at my install setup to check the original stuff...

Either someone else can chime in on it, or I'll get a look a bit later and get back to you....