PIC C Compiler and HC-SR04 Ultrasonic Sensor

What is wrong. The below code. Please help me.

#include "C:\Users\enhee\Documents\lcd16f873a.h"
#define use_portb_lcd TRUE
#include <LCD.C>
#byte timer1=0x10
#bit  trigger=0x07.2
#bit  echo=0x07.1
#bit on_off=0x10.0

unsigned char zai=12;

void main()
{
  float a;
  set_tris_c(0x02);
  timer1=0x10;

  setup_adc_ports(NO_ANALOGS);
  setup_adc(ADC_OFF);

  setup_spi(SPI_SS_DISABLED);

  setup_timer_0(RTCC_INTERNAL|RTCC_DIV_1);
  setup_timer_1(T1_DISABLED);
  setup_timer_2(T2_DISABLED,0,1);

  setup_comparator(NC_NC_NC_NC);
  setup_vref(FALSE);

  lcd_init();
  lcd_gotoxy(1,1);
  printf(lcd_putc,"zai medregch");

  for(;;)
  {
    set_timer1(0x0000);
    trigger=1;
    delay_us(10);
    trigger=0;

    while(!echo);       //Waiting for Echo
    on_off = 1;         //Timer Starts
    while(echo);        //Waiting for Echo goes LOW
    on_off = 0;         //Timer Stops

    a=get_timer1();
    a = a/58.82;
    a = a + 1;

    if(a>=2 && a<=400)   //Check whether the result is valid or not
    {
      lcd_gotoxy(1,2);
      printf(lcd_putc,"zai=%f cm",a-4);
    }
    else
    {
      lcd_gotoxy(1,2);
      printf(lcd_putc,"heterhii hol bna");
    }
    delay_ms(200);
  }
}