did you check for boms that loop back to themselves ?
 
 
SM-J-Q BOM Recursion Utility
 
I had that happen once
 
bom called another bom that called the 1st bom
 

took a bit of digging but it would seem that you have a BOM in BKBMMSTR.B  with the parent part of "       " (blank)  and it has 4 lines, one of those lines has the component of  "ALLOY STEEL" (one of your most common parts..) and when it was hitting this component with a blank parent it was getting stuck in an infinite loop.
 
Use Maintain Database and open BKBMMSTR.B   sort by BKBM.PARENT (that is the default) and delete those first 4 lines where the parent is blank.
to delete them check the Edit box on, then highlight the row you want to delete and press the delete key.
 
when done check off the edit box.
 
I ran MRF on your data and it took 4 minutes once that was fixed.