Hi,
I use Mach4 and have done for 8.5 years, and Mach3 before that. The Run From Here (RFH) command does work but there is a procedure that you have to follow to the letter or it will crash.
Its all about the preparatory move.....if you get that right you're OK. Misunderstand and CRASH!!!
Its been so long since I used Mach3 RFH that I doubt I could advise you well.
Mach4 is light years ahead.
Craig