Error on custom module in Receiver File Adaptor

Hi,

I am working on conversion of xml file to PDF file with the help of this blog..

[https://www.sdn.sap.com/irj/scn/weblogs?blog=/pub/wlg/2072] [original link is broken] [original link is broken] [original link is broken];

getting error in Message Monitoring.

Delivery of the message to the application using connection File_http://sap.com/xi/XI/System failed, due to: com.sap.aii.af.ra.ms.api.RecoverableException: Exception thrown in method process. The transaction is marked for rollback.: com.sap.engine.services.ejb.exceptions.BaseTransactionRolledbackLocalException: Exception thrown in method process. The transaction is marked for rollback..

how can i solve this error..

Thanks ,

syed