Help with configuring

[financecatalyst]

Hello there. I have written a simple code but it seems not to work properly. I am not sure what I am missing here and any help will be appreciated.

The code is as follows:

#CONFIG
    ifdef PM_USED
        device  pic16F688, intrc_osc_noclkout, wdt_on, mclr_on, protect_off
    else
        __config _INTRC_OSC_NOCLKOUT & _WDT_OFF & _PWRTE_ON & _MCLRE_OFF & _CP_ON & _CPD_ON & _BOD_ON & _IESO_ON & _FCMEN_ON
    endif
#ENDCONFIG
DEFINE OSC 8       ' OSCCON defaults to 8MHz on reset
DEFINE NO_CLRWDT 1
Include   "modedefs.bas"

' declare the interrupt handler
define INTHAND _ISR

goto main

ISR:
asm

; my asm code

endasm

main:
        PAUSE 50
	OSCCON = %01110001 ' Internal Oscillator 8MHz
        TRISA = %000100
        TRISC = %000010
        CMCON0 = 7
        ANSEL = 0               ' NO ANALOGS
        OPTION_REG = %10000011  ' RAPU = off, PS 1:16 to TMR0
        PORTA=0
        PORTC=0
        
        ' setup iZCD to interrupt on change
'        INTCON= %10110000
        '         |         Global interrupts enabled
        '           |       Timer0 interrupt enabled
        '            |      Zero Crossing interrupt enabled
        '             ----  Flags are cleared
 while 1
	toggle PortA.4
	pause 500
wend

When I comment the INTCON, my led blinks fine @ 500mS. When I uncomment it, the timings go out.
I want to run my PIC16F688 at internal 8MHz and not sure if I am missing any configuration register.