Its has to do with the MEN This is what I have used to make my stuff work. Found in the 18F4550.INC file in your PBP directory. The commands below work with MPASM v5.01

Code:
    else
        LIST
        LIST p = 18F4550, r = dec, w = -311, f = inhx32
        INCLUDE "P18F4550.INC"	; MPASM  Header
        ;__CONFIG    _CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
        ;__CONFIG    _CONFIG1H, _FOSC_HSPLL_HS_1H
        ;__CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_128_2H
        ;__CONFIG    _CONFIG3H, _PBADEN_OFF_3H
        ;__CONFIG    _CONFIG4L, _LVP_OFF_4L & _ICPRT_OFF_4L & _XINST_OFF_4L

        CONFIG PLLDIV = 5, CPUDIV = OSC1_PLL2, USBDIV=2
        CONFIG FOSC = HSPLL_HS
        CONFIG WDT=OFF, WDTPS=128
        CONFIG PBADEN = OFF
        CONFIG LVP=OFF, ICPRT=ON, XINST=OFF
        CONFIG MCLRE=OFF,BOR=SOFT,FCMEM=ON,IESO=ON,PWRT=ON,VREGEN=ON

        NOLIST
    endif