I just opened the 18F4550.inc file...look what you got at the end of...
Code:
_DEVID1          EQU  H'3FFFFE'
_DEVID2          EQU  H'3FFFFF'

_IDLOC0          EQU  H'200000'
_IDLOC1          EQU  H'200001'
_IDLOC2          EQU  H'200002'
_IDLOC3          EQU  H'200003'
_IDLOC4          EQU  H'200004'
_IDLOC5          EQU  H'200005'
_IDLOC6          EQU  H'200006'
_IDLOC7          EQU  H'200007'
Sure there's something to do with it...