i would like to be helped with clearing yhe errors in this program

#include<reg51.h>
#include<GSM_init.h>
unsigned char L,Lg[12],key,x[4],Po,count,z;
bit f2,f3,f4,f5;
sbit IOE1=P3^7; sbit IOE2=P3^6;
sbit m1=P1^0;sbit m2=P1^1;
sbit m3=P1^2;sbit m4=P1^3;sbit as=P3^2;sbit cs=P1^7;sbit ent=P3^3; sbit inc=P3^4;sbit dec=P3^5;
void main(void);
void serial(void) interrupt 4 using 1
{ if(RI)
{ a[i]=SBUF;
RI=0;
if(SBUF=='*')
{ f2=1;
EA=0;
} i++;
if(SBUF=='$')
{ i=0;
} }
} void clear()
{ for(i=0;i<42;i++)
{ a[i]='\0';
} }
GPS_track()
{ IOE1=1;
IOE2=0;
ES=1;
cmd(0x80);

11: sconf1();
EA=1;
delay(50);
EA=0;
if(a[0]=='G' && a[1]=='P' && a[2]=='G' && a[3]=='G' &&a[4]=='A' && a[27]=='N')
{ goto 12;
} Else
{ clear(); EA=1;goto 11;
} 12: cmd(0x01); cmd(0x80);
for(i=6;i<22;i++)
{ DT(a[i]);
} cmd(0xc0);
for(i=22;i<38;i++)
{ DT(a[i]);
} Po=0;
for(i=17;i<29;i++)
{ Lg[Po]=a[i];Po++;
} IOE1=0;
IOE2=1;
GSM_setup();
EA=0;
serial_tx("AT+CMGS=");
serial_tx1(0x22);
serial_tx("+255712279439");
serial_tx1(0x22);
serial_tx1(0x0d);
delay(10);
serial_tx("Logitude:");
for(i=0;i<4;i++)
{ serial_tx1(Lg[i]);
} serial_tx(" Latitude:");
for(i=5;i<11;i++)
{ serial_tx1(Lg[i]);
} serial_tx1(0x1a);
cmd(0x01);
DTS("msg sent");
for(i=0;i<42;i++)
{ a[i]='\0';
} EA=1;
cmd(0x01);cmd(0x80);DTS("welcome");
} void start()
{ m1=1;m2=0;m3=1;m4=0;
} void stop()
{ m1=1;m2=1;m3=1;m4=1;
} void main()
{ IOE1=0;
IOE2=1;
GSM_setup();
L=0;f2=0;f3=0;f4=0;f5=0;key=0;
while(1)
{ EA=1;count=0;cmd(0x01);
key=0;Po=0;
goto j2;
j1: key=0;Po=0;
cmd(0x80);DTS("Password :");
j2: if(ent==0)
{ while(ent==0);
while(count<2 && f4==1)
{ cmd(0x80);
DTS("Password :");
cmd(0x8a+Po);
DT(key+0x30);
if(inc==0)
{ while(inc==0);
if(key<9 && key>=0)
{ key++;
} else
{ key=0;
} }
else if(dec==0)
{ while(dec==0);
if(key<9 && key>0)
{ key--;
} else
{ key=0;
} }
else if(ent==0)
{ while(ent==0);
key=0;
Po++;
} x[Po]=key+0x30;
if(Po>=4)
{ if(x[0]=='1' && x[1]=='2' && x[2]=='3'&& x[3]=='4')
{ cmd(0x01);cmd(0xc0);DTS("correct pass u can");
delay(100);cmd(0x01);
delay(10);f4=0;f3=0;
count=0;
} else
{ cmd(0x01);cmd(0xc0);DTS("incorrect pass pls try");
count++;a[4]="";key=0;
delay(10);cmd(0x01);
goto j1;
} }
} }
if(count>=2)
{ cmd(0x01);cmd(0x80);DTS("Due to wrong pass");
cmd(0xc0);DTS("Vehicle P blocked");
while(1) ;
} if(cs==0 && as==1 && f3==0)
{ start();
cmd(0x01);cmd(0x80);DTS("vehicle is going");
} else
{ stop();
if(as==0)
{ f3=1;
cmd(0x01);cmd(0x80);DTS("vehicle is crashed");
EA=0;
serial_tx("AT+CMGS=");
serial_tx1(0x22);
serial_tx("+255712279439");
serial_tx1(0x22);
serial_tx1(0x0d);
delay(10);
serial_tx(" ur vehicle is crashed");
serial_tx1(0x1a);
clear();
i=0;
delay(100);
EA=1;
f1=wait();
if(f1!=1)
{ goto intim;
} f1=0;
clear();L=0;i=0;
GPS_track();
} }
while(f2==1)
{ i=0;
cmd(0x01);cmd(0xC0);
while(a[i]!='#')
{ i++;
} z=i;
for(i=z+1;a[i]!='*';i++)
{ DT(a[i]);
} delay(300);
if(a[z+1]=='B' && a[z+2]=='L' && a[z+3]=='O' &&a[z+4]=='C' && a[z+5]=='K' && a[z+6]=='*')
{ cmd(0x01);cmd(0x80);DTS("vehicle is blocked");
delay(300);
stop();
f3=1;f4=1;
} else if(a[z+1]=='T' && a[z+2]=='R' && a[z+3]=='A'&& a[z+4]=='C' && a[z+5]=='K' && a[z+6]=='*')
{ cmd(0x01);cmd(0x80);DTS("vehicle isTracking");
delay(200);cmd(0x01);clear();
GPS_track();
f1=0;
} i=0;z=0;
for(i=0;i<43;i++)
{ a[i]='\0';
} f2=0;
EA=1;
} cmd(0x01);cmd(0xc0);DTS("Waiting for mess");
} }