Hi Sai,
So have you activated the OData Service ERP_BUPA_ODATA ?
Have you tried running the OData Service ERP_BUPA_ODATA in the Gateway Client to check it is working and to see what data it is returning ?
I can't see any specific config instructions for ERP in the doco so perhaps you should also raise a SAP Message requesting details on what config needs to be done in ERP to ensure the OData Service retrieves the correct information
Rgds,
Jocelyn