LPC2148 code is not executing

Hi,

I have an epic problem with LPC2148. I am able to write a code in its flash memory however core is not executing a code. I tried following LED blinking code. Also I checked for crystal, its working fine (observed 12MHz waveform on oscilloscope).

#include <lpc21xx.h>

//void delay(void);

int main(void)
{ IO0DIR = 0xFFFFFFFF; // Configure all pins on Port 0 as Output IO0SET = 0xFFFFFFFF; // Turn on LEDs

while(1) {

} return 0;
}

/*void delay(void)
{ int z; for(z=0; z<4000; z++);
}