Hi praveenchappa and welcome to the monastery.

Without seeing all of the code and input data, it'll be hard for anyone to debug. There are some good tips above about how you should go about debugging yourself. But getting all the quoting and escaping correct is likely where the problem is. It will be much easier on you if you use one of the CPAN modules like JSON or JSON::XS which can take a perl hash as input and encode json strings for you.