Hi Neha,
The exception(Class Not Found) you mentioned above, says the particular class is not available in the RAM at the time of execution.
Please check your server/console logs If It says Steplet class not found then check your class path in the Agentry.ini file else for other classes(Stephandler, BAPI) check parameter mapping tab of the config panel If you have used factory design pattern to create the instances.
Note :- Please don't forget to restart the Agentry server If you do any changes in Agentry.ini file or in parameter mapping of the config panel .
Thanks,
Sudhir.