hi,

(mov IPL0, #10H)
(mov IPH0, #00H)

I have not received your reply on my private mail so it case you do not receive it here is the answer:

As far as I know, 87C51Fx has not IPL0/IPH0 registers but IP and IPH instead.
Okay, I have looked at its include file Keil\C51\ASM\Reg51f.inc and found:

IP DATA 0B8H
IPH DATA 0B7H
So you should use:

mov IP, #10H
mov IPH, #00H

Regards,
Oleg