You have to instruct PBP to reserve space for ICD variables. Look in your PBP directory for ICDDEFS.BAS (or one specifically for the target processor you're using). There are several. If there isn't one for the target you're using, it's simple enough to create your own.

Include one for the target processor you're compiling for.

INCLUDE "ICDDEFS4.BAS" would be for the 18F252/258/452/458 series.