Hi Avinash,
The null variable newChild is going to exist in the w3c dom parsing code so there is some issue happening within the imported libraries. I would suggest taking one of the failed messages and using the stack trace as the output when the exceptions occur so you can see where exactly the failure is happening.
That doesn't make any sense that running it in the ESR works for the same failed message unless there are some memory issues going on when the message is transformed.
Regards,
Ryan Crosby