Where did you get the software? Does not sound like a good copy.
LEADCOMP.dat was a optional file. Some machines had it if necessary. Decide by Bridgeport. The software would look for it but if not found would continue to boot.
If I detect corrupted software, I try and back up BMDCPRMS.sys and LEADCOMP.dat (again if it is there). Then I will do a SCANDISK to see if there are any bad sectors. Depending on the age of the hard drive, I might recommend a DOM (solid state drive) from EMI.
Typically I start from scratch. Fdisk at the 504 MB making it a active DOS partition. Then I load in full DOS 6.20 followed by the machine software. If the original BMDCPRMS file cannot be copied, the install generates a good copy minus the backlash, pitch error comp, TC height and orient, spindle speeds, spindle gain, etc. All the stuff unique to a machine. These you have to figure out and input.
George
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)