resolving C202 error

Hi, I have been working on a project which requires interfacing a keypad and a LCD to 8051 microcontroller using keil software(microvision version 5). I have difficulty resolving a C202 error, error statement being ‘PIN_Dx’: undefined identifier. (x being 0,1,2,3,4,5,6,7)
I have attached the source code below. Please help

#include <reg51.h>
#include <string.h>
#define lcd_4bit P1
#define keypad P2
char u1[]="0001",U2[]="0002",U3[]="0003",p[10],k,v1[10];
void lcd_init();
void lcd_cmd(unsigned char b);
void lcd_str(unsigned char a);
void gotoxy(int x,int y);
void lcd_clear();
void lcd_array(char *a);
int i=0,d1,d2,d3,z1=1,z2=1,z3=1;

int key();
int key()
{
while(1)
   {
     output_low(PIN_D4);
     output_high(PIN_D5);
     output_high(PIN_D6);
     output_high(PIN_D7);
     if(input(PIN_D0)==0)
     {
     while(input(PIN_D0)==0);
     return('7');

     goto k;
     }
     else if(input(PIN_D1)==0)
     {
    while(input(PIN_D1)==0);
     return('4');

     goto k;
     }
     else if(input(PIN_D2)==0)
     {
       while(input(PIN_D2)==0);
     return('1');

      goto k;
     }
     else if(input(PIN_D3)==0)
     {
       while(input(PIN_D3)==0);
     return('c');

    goto k;
     }
     output_high(PIN_D4);
     output_low(PIN_D5);
     output_high(PIN_D6);
     output_high(PIN_D7);
     if(input(PIN_D0)==0)
     {
 while(input(PIN_D0)==0);
     return('8');

      goto k;
     }
     else if(input(PIN_D1)==0)
     {
    while(input(PIN_D1)==0);
     return('5');

      goto k;
     }
     else if(input(PIN_D2)==0)
     {
     while(input(PIN_D2)==0);
     return('2');

      goto k;
     }
     else if(input(PIN_D3)==0)
     {
     while(input(PIN_D3)==0);
     return('0');

      goto k;
     }



     output_high(PIN_D4);
     output_high(PIN_D5);
     output_low(PIN_D6);
     output_high(PIN_D7);
     if(input(PIN_D0)==0)
     {
 while(input(PIN_D0)==0);
     return('9');

      goto k;
     }
     else if(input(PIN_D1)==0)
     {
     while(input(PIN_D1)==0);
     return('6');

      goto k;
     }
     else if(input(PIN_D2)==0)
     {
        while(input(PIN_D2)==0);
     return('3');

     goto k;
     }
     else if(input(PIN_D3)==0)
     {
    while(input(PIN_D3)==0);
     return('=');

     goto k;
     }



     output_high(PIN_D4);
     output_high(PIN_D5);
     output_high(PIN_D6);
     output_low(PIN_D7);
     if(input(PIN_D0)==0)
     {
     while(input(PIN_D0)==0);
     return('/');

    goto k;
     }
     else if(input(PIN_D1)==0)
     {
     while(input(PIN_D1)==0);
     return('*');

     goto k;
     }
     else if(input(PIN_D2)==0)
     {
    while(input(PIN_D2)==0);
     return('-');

     goto k;
     }
     else if(input(PIN_D3)==0)
     {
       while(input(PIN_D3)==0);
     return('+');

    goto k;
     }
   }

   k:
   delay_ms(1);
}

void lcd_init();
void lcd_cmd(unsigned char b);
void lcd_str(unsigned char a);
void gotoxy(int x,int y);
void lcd_clear();
void lcd_array(char *a);
void lcd_init()
{
lcd_cmd(0x02);
lcd_cmd(0x28);
lcd_cmd(0x0c);
lcd_cmd(0x06);
lcd_cmd(0x80);
}

void lcd_cmd(unsigned char b)
{
int b1;
b1 = (b & 0xF0);
output_b(b1);
 output_high(PIN_B2);
delay_ms(1);
output_low(PIN_B2);

b1 = ((b<<4) & 0xF0);
output_b(b1);
 output_high(PIN_B2);
delay_ms(1);
output_low(PIN_B2);
}

void lcd_str(unsigned char a)
{
int a1;
a1=(a&0xF0);
output_b(a1 | 0x01);
output_high(PIN_B2);
delay_ms(1);
output_low(PIN_B2);

a1=((a<<4)&0xF0);
output_b(a1 | 0x01);
output_high(PIN_B2);
delay_ms(1);
output_low(PIN_B2);
}

void gotoxy(int x,int y)
{
if(y==0)
{
lcd_cmd(0x80+x);
}
else if(y==1)
{
lcd_cmd(0xc0+x);
}
}
void lcd_clear()
{
lcd_cmd(0x01);
lcd_cmd(0x80);
}
void lcd_array(char *a)
{
while(*a)
{
lcd_str(*a++);
}
}

char u1[]="1234",U2[]="9876",p[10],k,v1[10];
int i=0,d1,d2,z1=1,z2=1;
void main()
{
char m[30];
lcd_init();
 lcd_str("Password Based");
    gotoxy(0,1);
    lcd_str("Circuit Breaker");
    delay_ms(1500);

l1:


    lcd_clear();

    lcd_str("Enter Password:");
    gotoxy(0,1);
   while(1)
   {
    k=key();
    if(k=='c')
    {
    lcd_clear();
    gotoxy(0,0);
    lcd_str("Enter Password:");
    gotoxy(0,1);
    i=0;
    }
    else if(k=='=')
    {
    p[i]='\0';
    goto l;
    }
    else
    {
    lcd_str(k);
    p[i]=k;
    i++;
    }

   }
   l:
   gotoxy(0,1);
   d1=strcmp(u1,p);
   d2=strcmp(u2,p);

   if(d1==0)
   {

   gotoxy(0,0);
   lcd_str("Correct Password");
   gotoxy(0,1);

   if(z1==1)
   {
   output_bit(PIN_C0,1);
   lcd_str("Load 1 Active");
   delay_ms(300);
   z1==0;
   goto l1;
   }
   else if(z1==0)
   {
   output_bit(PIN_C0,0);
   lcd_str("Load 1 Inactive");
   delay_ms(300);
   z1==1;
   goto l1;
   }
   }



  else if(d2==0)
   {

   gotoxy(0,0);
  lcd_str("Correct Password");
   gotoxy(0,1);


  if(z2==1)
   {
   output_bit(PIN_C1,1);
   lcd_str("Load 2 Active");
   delay_ms(300);
   z2==0;
   goto l1;
   }
   else if(z2==0)
   {
   output_bit(PIN_C1,0);
   lcd_str("Load 2 Inactive");
   delay_ms(300);
   z2==1;
   goto l1;
   }
   }
 else
 {
 lcd_clear();
 lcd_str("Wrong Password");
 delay_ms(300);
 goto l1;
 }
   }