I do not have this chip but give this a shot
Code:
'18F4523 INTERNAL OSC 8MHZ Internal oscillator block, port function on RA6 and RA7	
@ __CONFIG    _CONFIG1H, _OSC_INTIO67_1H  & _FCMEN_OFF_1H & _IESO_OFF_1H
@ __CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_512_2H
@ __CONFIG    _CONFIG3H, _CCP2MX_PORTC_3H & _PBADEN_OFF_3H & _LPT1OSC_OFF_3H & _MCLRE_ON_3H
@ __CONFIG    _CONFIG4L,  _STVREN_ON_4L & _LVP_OFF_4L & _XINST_OFF_4L
DEFINE OSC 8
OSCCON = %01110000
ADCON1 = %00001111  
CMCON = 7

Main:
TOGGLE PORTE.0
PAUSE 1000
GOTO Main