TMR0 and SERIAL both ISR not working in single program

void UART_INIT(void)
{
	TXD		=	1;			//TXD Pin set as I/P		
	RXD		=	1;			//RXD Pin set as I/P		
	SCON	=	0x50;		//mode1, 8bit UART, Reception Enable
	TMOD 	= 	0x20;		//timer 1 8-bit auto-reload
	TH1 	= 	UART_SetBaudRate(CLK_110592, 
				UART_BAUD_9600);		//Baud Rate 9600 8-n-1
	TL1 	= 	TH1;						//Reload count
	ES		=	ACTIVE_HIGH_ON;	       //Enable Serial Intr 
	PS		=	ACTIVE_HIGH_ON;		//Set High Priority of Serial Intr
	EA		=	ACTIVE_HIGH_ON;		//Enable Global Intr
	TR1 	= 	ACTIVE_HIGH_ON;					// Start timer
}

void ISR_UART(void) interrupt 4 
{
     if	(RI)
    {
         //copying the SBUF in the buffer and checking whether whole frame is       
         // received or not
        
     }
}

void TIMER_INIT(void)
{
	TMOD	|=	0X01;
	TH0		=	0XFC;	//1MSEC COUNT 65535-922
	TL0		=	0X66;

HIGHPRIORITY_TIMER0INTR	=	ACTIVE_HIGH_OFF;	//Set Timer0 interrupt as  
                                                                                //low priority

	ENABL_ETIMER0INTR		=	ACTIVE_HIGH_ON;
	ENABL_GLOBALINTR		=	ACTIVE_HIGH_ON;
}

void ISR_TIMER0(void) interrupt 1  //using 2
{
	TIMER0_INTR_FLAG	=	ACTIVE_HIGH_OFF;
	START_TIMER0		=	ACTIVE_HIGH_OFF;
	TH0					=	0XFC;	//TIMER OF 1MSEC
	TL0					=	0X66;
	START_TIMER0		=	ACTIVE_HIGH_ON;

	if(u8_ColumnNo>15)
	{
		  u8_ColumnNo		=	0;
		  Enable_74LS138	=	1;
	}
	ROW_0_TO_7		=	0xFF;
	ROW_8_TO_15		=	0XFF;
	COLUMN_0_TO_7	=	~(1<<u8_ColumnNo);
	if(u8_ColumnNo>=8)
	{
		COLUMN_8_TO_15	=	COLUMN_8_TO_15 + 0X10;
	}
	ROW_0_TO_7		=	u8_DisplayBuffer[u8_ColumnNo<<1];
	ROW_8_TO_15		=	u8_DisplayBuffer[(u8_ColumnNo<<1)+1];
	u8_ColumnNo++;
	
	
}