microcontroller problem, urgent please

hello,
m doing a mini project based on microcontroller, at89s52. m getting a warning while convertin my code to hex code. 😕 the warning is coming in this way,
WARNING L4:data space memory overlap
FROM: 0000H
TO: 0027H
PROGRAM SIZE: DATA=48.0 xdata=0 code=561
0 errors, 1 warning

m not gettin wat is d exact prob.... is it a logical error?? if so how shall i remove it?? 😔 please help me to debug d program. m using KEIL to convert it into hex.... is it KEIL software's prob?? should i use RIDE? wats d difference between these two??
i no, i m sendin a bigger post. But please do read n help me soon....😭