my project

HELLO I HAVE WRITTEN A "C CODE WITH REFERENCE TO 8051 FOR MY PROJECT" I HAVE TO COMPARE STRINGS HERE BUT I AM GETTING ERROR C214 ie ILLEGAL USE OF POINTER. NOW I HAVE NO IDEA HAT IS THIS AND HOW TO DEAL WITH THIS??? PLZ HELP ME. THIS IS THE ONLY ERROR IN MY PROG.

#include <stdio.h>
#include <reg51.h>
#include <string.h>

char arr1[19];
char arr[]={'A','T','+','C','M','G','F','=','1'};
int i,j=0,k,m,r,s,t;

sbit port1_0 = P1^0;
sbit port1_1 = P1^1;
char string1[] = ('O','K');
char string2[] = ('+','C','M','G','R',' ','S','M',' ','1',' ','#','F','A','N','1',' ','O','N');
char string3[] = ('+','C','M','G','R',' ','S','M',' ','1',' ','#','L','G','T','1',' ','O','N');
void serial_isr();
void send2ndstring();

void main()
{

for(i=0;i<=9;i++) { SBUF=arr[i]; while(TI==0); }

}

void serial_isr() interrupt 4
{ if(RI==0) { //while(TI==0); //subroutine1// TI=0; }

if(RI==1) { RI=0; arr1[j]=SBUF; j++; }

r=strcmp(string1,arr1[j]); //as per keil err is here// s=strcmp(string2,arr1[j]); t=strcmp(string3,arr1[j]);

if(r==0) { send2ndstring(); }

if(s==0) { port1_0=1; } else { port1_0=0; }

if(t==0) { port1_1=1; } else { port1_1=0; }
}

void send2ndstring()
{ char arr2[]={'A','T','+','C','M','G','R','=','1'};

for(m=0;m<9;m++) { SBUF=arr2[m]; while(TI==0); }
}

PLZ HELP ME OUT AS SOON AS POSSIBLE