how to create monitor program to suit a particular hardware requirement

Dear sir,
My Kiel key no is XXXXX-XXXXX-XXXXX. I wanted to have a monitor program by which I can load application in a RAM and execute from there.When I read document of MON51.PDF I came to know that just by customizing startup.A51 and install.A51 & running install.bat file in MS-DOS we get mon51.hex.
our hardware requirement is like this
1)Atmel 89c52 microcontroller
2)0000h-7FFFh (External PRom)
C000h-DFFFh (External Ram)
I want monitor program to reside in External Prom (0000-7fffh) and load application program
in External Ram (c000h-DFFFh).For local variables xdata ranging from DF00-DFFFh.

The following changes I made in
1)c51\lib\startup.A51
CSEG AT 0C000h
?c_startup:LJMP startup1

2)c51\mon51\Install.A51
INT_ADR_OFF EQU 0c000h
DEF_PC_VAL EQU 0C000h

but when i ran Install.bat in DOs prompt with command
install 0 DF C0
the following error i got
1)code must be above (4000h)


so please advice me whether my approach was correct if not give me the exact procedure to suit my above requirements.

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