Mahesh,
you wrote

It worked normal also after first programming in the system. But , to my horror, when I tried to reconnect it with Falsh Magic again, it still runs the normal program ! If I use the chip HBP in the same system, I can get connected. Is it possible that the chip is damaged?


and then

Also it happened with HBP chip a couple of times that it was running the program instead of getting connected to Flash Magic.

It looks as though your flash magic's performance is not very stable. If you get problems with "BN" chip, but occasionally also the "hbp" chip fails, I would suspect the "flash magic" as it is the common part in both problems.



Regards
Patrick