3232504 - Unable to create EricContext due to: while trying to invoke the method java.lang.Object.hashCode() of a null object loaded from local variable 'key'

You are facing an issue when running HCM ELSTER scenario using PI/PO system as middleware.

XPI inspector shows the exact error which is similar to this:

Caught java.lang.RuntimeException: Unable to create EricContext due to: while trying to invoke the method java.lang.Object.hashCode() of a null object loaded from local variable 'key'
at com.sap.fin.xi.elster.eric.EricContext.buildContext(EricContext.java:176)
at com.sap.fin.xi.elster.eric.EricContext.<init>(EricContext.java:115)
at com.sap.fin.xi.elster.eric.ERiCModule.process(ERiCModule.java:212)
at com.sap.fin.xi.elster.ElsterHCMSendModule.process(ElsterHCMSendModule.java:30)
at sun.reflect.GeneratedMethodAccessor876.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
...

SAP NetWeaver
SAP Process Integration/Orchestration
Elster 2.1 

SAP, PI, PO, ELSTER, HCM, moduel, RFC, SOAP, sender channel, receiver channel, EricContext,  Unable to create EricContext, Object.hashCode, null object, local variable 'key' , KBA , BC-XI-CON-ELS , HR/FI Elster Module for PI , Problem