file to idoc scenarion in PI 7.31

Hi Experts,

I am working on file to IDOC scenarions ( ACLPAY01 ) but getting the following error message

Adding control record to payload failed due to Error during transform: java.lang.NullPointerException: while trying to invoke the method java.lang.String.length() of a null object loaded from local variable chars

Error MP: exception caught with cause com.sap.aii.af.idoc.exception.IDOCAdapterException: Error during transform: java.lang.NullPointerException: while trying to invoke the method java.lang.String.length() of a null object loaded from local variable 'chars'

Exception caught by adapter framework: Error during transform: java.lang.NullPointerException: while trying to invoke the method java.lang.String.length() of a null object loaded from local variable 'chars'

Error Transmitting the message to endpoint <local> using connection File_http://sap.com/xi/XI/System failed, due to: com.sap.aii.af.idoc.exception.IDOCAdapterException: Error during transform: java.lang.NullPointerException: while trying to invoke the method java.lang.String.length() of a null object loaded from local variable 'chars'

Help is highly regarded

Regards,

Krutiman