Swift FileAct *.par file Error.

Hi PI Experts

In SAP PI we have installed Swift 7.X version . As per Swift standard interface should generate 2 files (Payload / par file ) based on BCM payment XML file . 1st payload file has been generated successfully. However it is not generating 2nd *par file .. I am getting below error.

'MP: exception caught with cause com.sap.engine.interfaces.messaging.api.exception.MessagingException: java.lang.NullPointerException: while trying to invoke the method java.lang.Object.getClass() of an object loaded from local variable 'objMessage''

Swift Configuration I have done base on SAP NO.0001303428

Regards

Inder