KEIL asm program error

Hello, I am having problem with program written with KEIL: *** error 65: access violation at I:0x81 : no 'write' permission. Can't find sollution myself, could you help?
This program takes info from ADC and writes it to RAM (100 samples). These is also delay routine with a 10x10ms=100ms.

ADC is AD573, processor - 8051.

RAM equ 0000H
ADC_CONV equ 4000H
ADC_READ_HBE equ 8000H
ADC_READ_LBE equ 0C000H
ADC_NIN equ 100
TIMER_MULTIP equ 10

ORG 0000H
SJMP MAIN
ORG 0040H

MAIN: MOV R1, #ADC_NIN
WAIT1: MOV DPTR, #ADC_CONV
MOVX @DPTR, A

WAIT2: JNB P3.2, WAIT2

LCALL READ

READ: MOV DPTR, #ADC_READ_HBE
MOVX A, @DPTR
MOV DPTR, #RAM
MOVX @DPTR, A
INC DPTR
MOV R2, DPH
MOV R3, DPL

MOV DPTR, #ADC_READ_LBE
MOVX A, @DPTR
ANL A, #0C0H
MOV DPH, R2
MOV DPL, R3
MOVX @DPTR, A
INC DPTR
MOV R2, DPH
MOV R3, DPL

LCALL DELAY

WAIT3: DJNZ R1, WAIT1

RET

DELAY: MOV TMOD,#01
MOV R0,#TIMER_MULTIP

WAIT4: MOV TH0,#0D8H
MOV TL0,#0EFH

SETB TR0

FLAG: JNB TF0, FLAG

CLR TR0
CLR TF0
DJNZ R0, WAIT4
RET

END

Well, maybe you could justl tell if I had explained the problem correctly or no.