This is the code, using PBP3, Micro Code Studio Plus, and a 16F648A PIC selected:

INCLUDE "ALL DIGITAL.pbp"
LED var PORTA.0

mainloop:
HIGH LED
PAUSE 500
LOW LED
PAUSE 500
GOTO MAINLOOP
END

I get this message at the bottom:

WARNING: Unable to open INCLUDE file ALL DIGITAL.pbp

I have been unable to determine the reason I am getting this message.
Thank you very much for your help.