Debugger Microchip MPLAB ICD 2, jeho klony (SPCD) a PICkit 2

uspesne jsem naprogramoval PIC16F84A ale kdyz chci programovat PIC16F877 tak se stahuje novej OS jenomze pri tom to vyhodi:

Downloading Operating System
ICD0152: Failed to read all of requested bytes (0x0 of 0x8)
…Download Operating System Failed
ICD0152: Failed to read all of requested bytes (0x0 of 0x2)

ne a ne se nahrat…
proc to nejde?
verze mplab je 8.50