1. the circuit used for the AT89S5X ISP is not safe for the microocntroller. it would have been better to use a RS232<->TTL convertor for all the RS232 lines used.
2. Weather the circuit works with the AT89S51/52 or not is still to be acertained, IT didnt work for me.
3.I am not a very good PC programmer, so i could not modify/compile the source code supplied.
4. But i am sure of the micorocntroller programming. So i am trying to make a programmer using a AT89C2051. on the PC side a terminal emulation program will send the hex or binary file and on the programmer side the AT89C2051 would understand all the commands and program the target micro.
5. I have reached midway in my second approach. and after a few more session i should be able to program the target using this approach.

vinod kumar