I guess, look in Mach4Hobby/Screens, and if that file is not there, that would explain that. Your profile is looking for that screen and it isn't there. I'm not sure modern versions of Mach4 install that screen, so if you've upgraded Mach4 but an old profile is looking for that screen, there you go.
One thing to remember, if you're going to edit a "stock" Mach4 screen, rename it before editing or it will be over written on a new install.