Program is not go in ISR during the interrupt

I write some simple programs but in all of them ISR is not executed during its interrupt occurance. i face similar problem in sample programs also. I face this problem after the installation of uVision software ver 3.03a, previously when i use uVision 3.0 it works fine. I try even the same programs that work in ver3.0 now in 3.03a but ISR is not executed.

i use uVision software version 3.03a and debug it with simulator (uC is LPC2364).

Plz anyone help me, my project is stuck due to this..
Here is the example of my program

#include<LPC21xx.H>
unsigned char half_sec,sec,i,j;

void timer0 (void) __irq
{

half_sec = ~half_sec;

T0IR = 0x01;

VICVectAddr = 0;
}

int main(void)
{

half_sec=0; sec=0; /*initialize timer0*/

T0MCR = 0x00000003;

T0MR0 = 0x000000E0;

T0TCR = 0x01;

VICIntEnable = 0x00000010;

VICVectCntl1 = 0x24;.

VICVectAddr1 = (unsigned long)timer0;

IO0DIR |= 0x00000004;

while(1)

{

if(sec==1)

{ for(j=1;j<=2;j++)

IO0SET = 0x00000004; //IO0PIN = 1;

}

if(half_sec == 1)

{

for(j=1;j<=2;j++)

IO0CLR = 0x00000004;

}

}

}