IDOC flat file to XML error

Hi Experts,

I need to convert flat idoc file to IDOC xml. I am using the module SAP_XI_IDOC/IDOCFlatToXmlConvertor in sencer file channel.SAP PI version 7.4.

I am facing the below issue in sende channel and the file is not picked up :

Sending file failed with java.lang.NumberFormatException: For input string: ""

The below log is availbe in log viewer :

Module Exception 'com.sap.aii.af.idoc.exception.IDOCModuleException: PSGNUM can not be identified for segment E1MBXYH.' found, cause: java.lang.NumberFormatException: For input string: ""

The doc format is as follows :

EDI_DC40_U 2 WMMBID02 WMMBXY

Please suggest how will this be resolved.

Thanks,

Merina