Naveen,
I believe this error is a result of missing libraries necessary for OTM to function. When you install OTM, it prompts you to download an install (manually) a lot of 3rd party libraries that are required by OTM, but which Oracle refuses to distribute with the product.
Rather than going through this tedious process, we're packaged up these additional libraries and you can find details here:
http://www.otmfaq.com/forums/f23/otm...tallation-415/ (OTM v5.5 Extra Jars Required for Installation)
--Chris