Take a look at this thread:
http://www.chiefdelphi.com/forums/showthread.php?t=25662&highlight=Invalid+Address%3 A+0x0+%28correct+Range%3A+0x800-0x7fff%29
found this by searching for:
Invalid Address: 0x0 (correct Range: 0x800-0x7fff)
(search on the Orange bar above the ads)
(change the 18f8720.lkr with 18f8722.lkr - in the answer)
Sean