Setting up SAP B2B Adapter for IDOCs

We are trying to set up SAP B2B Adapter for IDOCs. We have managed to create the partner profile and generate distribution model for the same. When we test the partner profile in SAP
(T-Code BDM5 in SAP), we get an error program WMB2BONIDES not registered.

WMB2BONIDES is the name of the RFC connection for B2B server at our site.

Can anyone help ? Many thanks in advance.