Re: Target has invalid calibration data (0x00)
Is the OP's error not the old chestnut of the oscillator calibration value being overwritten in these older devices, typically by erasing the chip without re-writing the original calibration value?
If it was erased, the programmer would read 0xfff - all '1'. Since the OP gets zeroes, this means the ICSPDAT line is stuck low. Thus the problem is that the PIC doesn't respond (most likely because the connection is bad).
Agreed, good point.