linking error in the program . can not find the solution

I am a newbee in Microcontroller programing . the code I have written in C was from a book and it is giving linker error. please help me to solve the problem.
I am sending the code:

/*reading pwm waveform and calculation of frequency using microcontroller*/
#include<reg52.h>
sbit RS=P2^0;
sbit RW=P2^1;
sbit EN=P2^2;

sbit IN=P2^4;

void delay(void);
void INIT(void);
void ENABLE(void);
void LINE(int);

int ONTIME(int);
int offtime(int);
/*declaration of functions complete*/
//
void LINE(int i)
{ if(i==1) { RS=0; RW=0; P1=0x80; ENABLE(); RS=1; } else { RS=0; RW=0; P1=0xC0; ENABLE(); RS=1; }
}

/*dealy subroutine*/

void delay(void)
{ int i,j; for(j=0;j<10;j++) { for(i=0;i<100;i++); }
}

/*delay complete*/

/*Enable subroutine*/
void ENABLE(void)
{ EN=1; delay(); EN=0; delay();
}

/*initialisation of LCD giving proper command*/

void INIT(void)
{ RS=0; RW=0; EN=0; P1=0x38;// 2 Lines and 5*7 matrix LCD ENABLE(); ENABLE(); ENABLE(); P1=0x06; // Shift cursor to left ENABLE(); P1=0x0E; //display on, cursor blinking ENABLE(); P1=0x01; //clear display screen ENABLE();
} /* measuring ontime*/
int ONTIME(int m)
{ if(m==1) { IN=1; /*input to 8051 is from 555 osc*/ TMOD=0x01; TR0=0; TF0=0; TL0=0x00; TH0=0x00; while(IN); /*check for rising edge*/ while(!IN); TR0=1; while(IN); TR0=0; }

/* TO MEASURE OFFTIME*/

if(m==2) { IN=1; TMOD=0x01; TR0=0; TF0=0; TL0=0x00; TH0=0x00;

while(!IN); // check for falling edge while(IN); TR0=1; while(!IN); // CHECK FOR RISING EDGE TR0=0; } return((TH0*256)+TL0);
}

void main(void)
{ int unit, tens, hundred, thousand, tenthou, x; char code dis3[]="Fre in HZ="; char *p; int i,j,k,freq,l; while(1) { for(x=1;x<=3;x++) { if(x==1) { i=ONTIME(x); k=i; }

if(x==2) { i=offtime(x); l=i; } if(x==3) { freq=k+1; i=1/freq; } }

unit=(i%10); tens=(i/10)%10; hundred=(i/100)%10; thousand=(i/1000)%10; tenthou=(i/1000)%10; unit=unit+0x30; tens=tens+0x30; hundred=hundred+0x30; thousand=thousand+0x30; tenthou=tenthou+0x30; INIT(); LINE(0);

p=&dis3;

for(j=0;j<8;j++) { P1=*p++; ENABLE(); }

LINE(2); P1=tenthou; ENABLE(); P1=thousand; ENABLE(); P1=hundred; ENABLE(); P1=unit; ENABLE(); }
}