rfid+microcontroller prblm

hi
i am connecting a simple passive rfid reader(with no additional features) to my microcontroller ds89c450(8051 compatible) , i have written a code for it
for this my rfid reader reads a tag and gives out 10 digits,it has rs232 connection,
so i am connecting my rfid reader with a rs232 db9 connector to my microcontroller( i am using built in kit for microcontroller so my rs232 stuff is built in for both)
i have pasted my code below
i have attached some leds to see the progress of my code on kit
as i observed running it .........
i found out tht
if we take negative logic
only led2 gets on
led 1 gets on but after sometime ,???even if i dont bring any tag nearby????
led3 ,4 never switches on
i have been able to analyze tht my init function running but wht abt others plzz help me out , wht might be the prblm
finally wht i can say is i sucessfully tested on keil this one is working 100%(even in debugging stg)

#include<reg420.h>
#include<string.h>

sbit buz1=P2^3;
sbit tagsw=P3^6;
sbit led1=P2^4;
sbit led2=P2^5;
sbit led3=P2^6;
sbit led4= P3^2;

init();
void rfid_num();
void tagfunc();
char *loc;

void main()
{

buz1=0;
init();//used to initialize my microcontroller

while(1)
{

while (RI_1==0);// am waiting for an receive interrupt led1=0;//test led
rfid_num();// as we receive i am calling this function
}

}

init()
{ led2=0; TMOD=0x21; TH1=0xFD;

TR1=1;

return ;
}

void rfid_num()

{ char *aradd,i ,tagno[10];//taking an array to store my tag no char *a= "34006CC5AA";//these are the tag nos

char *b= "34006CD97F";

char *c= "34006C8CA1";

char *d= "34006C6D26";

char *e= "34006CAC2F";

char *f= "34006C6170";

led3=1;

aradd=&tagno[0];

led3=0;

for(i=0;i<=9;i++)// i take up all nos in the tag

{ while(RI_1==0);

*aradd=SBUF1;

RI_1=0;

aradd++;

}

RI_1=0;

aradd=&tagno[0];

ES0=1;

if(!strcmp(aradd,a))// i am comparing here the present one with predefined for my future purpose in my educatioal project

{

led4=0; }

else if(!strcmp(aradd,b)) {

}

else if(!strcmp(aradd,c)) {

}

else if(!strcmp(aradd,d)) {

}

else if(!strcmp(aradd,e)) {

}

else if(!strcmp(aradd,f)) {

} tagfunc(); ES0=1; return;

}

void tagfunc()// i call this function from rfidnum func { buz1=1;

if(tagsw==0) { while(tagsw==0);

} else { while(tagsw==1);

} buz1=0;

return ; }