Hello,

I also encountered recently the same issue, using PBP v2.47 and MPLAB 7.30 and 7.51. I don't have the solution, but found in Microchip MPLAB Readmes, a piece of information that might be linked to the problem:
"Important MPLINK and MPLAB IDE Compatibility Note"
it explains that trying to link object files or libraries compiled with a recent release of MPLAB (after v7.21 probably ), with an old version of MPLINK (prior v4.00 ) will generate a similar message to the one we get with PBP:
"Error - Coff file format for 'yourfile.o' does not appear to be a valid COFF file."

Regards,