Has the OBD been created in ERP and failed to transfer to EWM? If not then surely this points to a problem with the data/customizing in ERP not EWM.
Have you created a plant customer and plant vendor in ERP and CIF'ed them to EWM? They should be created as Business Partners and you should see them in transaction BP.
Also make sure your Shipping Point and Sales Organization have been configured correctly in ERP.
Hope this helps.
