problem about memory map (8051)

hi all ...

after building my code, I want to debug with step into button to watch memory. however, whenever I press step into it gives an error like :

*** error 65: access violation at C:0x0000 : no 'execute/read' permission

I looked for MAP command. and made *.ini file in which I tiped
MAP 0x21, 0x7F READ WRITE
Am I mistaking with memory ranges ??

Source code is simply

org 2100h
setb P1.0
loop: mov C, P1.0
mov P1.7, C
sjmp loop
end

any help is appreciated