Help with I2C!!! I'm stucked.

#include "18F2520.h"
#include "f2520_regs.h"
#fuses INTRC
#use delay(clock=4000000)

#define RS PIN_A2
#define EN PIN_A1

void lcd_init();
void lcd_cmd(unsigned char);
void lcd_data(unsigned char);

/********** I2C functions**********/
void I2C_INIT();
void I2C_START();
void I2C_RESTART();
void I2C_STOP();
void I2C_ACK();
void I2C_NAK();
void I2C_WAIT();

void I2C_WRITE(unsigned char data);
unsigned char I2C_READ(void);

int16 READ_ADC();
unsigned int16 value, high_byte, low_byte, final_byte;

/*****************************************************************
						Main Function
*****************************************************************/
void main()
{
I2C_INIT();
lcd_init();

while(1)
{
value	=	READ_ADC();
lcd_cmd(0x80);
printf(lcd_data,"%5lu",value);
}
}

/**********************************************************************
						I2C Initialization
**********************************************************************/
void I2C_INIT()
{
TRIS_C3	=	1;				//	configures SCL and SDA pins as inputs
TRIS_C4 =	1;

SSPSTAT	=	0b10000000;		//	Slew rate disabled
SSPCON1	=	0b00101000;		//	SSPEN = 1, I2C Master mode, clock = FOSC/(4 * (SSPADD + 1))
SSPCON2	=	0b00000000;

SSPADD	=	0x28;			//	100 Khz @ 4 Mhz oscillator
}

void I2C_START()
{
SEN	=	1;
while(SEN);
}

void I2C_RESTART()
{
RSEN	=	1;
while(RSEN);
}

void I2C_STOP()
{
PEN	=	1;
while(PEN);
}

void I2C_ACK()
{
ACKDT	=	0;		//	Acknowledge data bit, 0 = ACK 
ACKEN	=	1;		//	ACk data enabled
while(ACKEN);		//	wait for ACK data to send on bus
}

void I2C_NAK()
{
ACKDT	=	1;		//	Acknowledge data bit, 1 = NAK
ACKEN	=	1;		//	ACK data enabled
while(ACKEN);		//	wait for ACK data to send on bus
}

void I2C_WAIT()
{
while((SSPCON2 & 0x1F) || (SSPSTAT & 0x04));		// wait for any pending transfer
}

void I2C_WRITE(unsigned char data)
{
SSPBUF	=	data;		//	Move data to SSPBUF
while(BF);				//	wait till complete data is sent from buffer
I2C_WAIT();				//	wait for any pending transfer
}


unsigned char I2C_READ(void)
{
unsigned char temp;
RCEN	=	1;			//	Enable data reception
while(!BF);				//	wait for buffer full
temp	=	SSPBUF;		//	Read serial buffer and store in temp register
I2C_WAIT();				//	wait to check any pending transfer
return temp;			//	Return the read data from bus
}


int16 READ_ADC()
{
I2C_START();
I2C_WRITE(0xD0);
I2C_ACK();
I2C_WRITE(0x88);
I2C_ACK();
I2C_RESTART();

I2C_WRITE(0xD1);
I2C_ACK();
low_byte	=	I2C_READ();
high_byte	=	I2C_READ();

final_byte	=	((high_byte << 8) | low_byte);
I2C_STOP();

return final_byte;
}

void lcd_init()
{
lcd_cmd(0x30);      // Configure the LCD in 8-bit mode, 1 line and 5x7 font
lcd_cmd(0x0c);      // display on and cursor off
lcd_cmd(0x01);      // clear display screen
lcd_cmd(0x06);      // increment cursor
lcd_cmd(0x80);      // set cursor to 1st line
}

void lcd_cmd(unsigned char c)
{
output_b(c);
output_low(RS);
output_high(EN);
delay_ms(15);
output_low(EN);
}

void lcd_data(unsigned char z)
{
output_b(z);
output_high(RS);
output_high(EN);
delay_ms(15);
output_low(EN);
}

while(!BF);