Dear Venkat,
This error is because that the data models in the R/3 system and in the CRM system differ.
In ECC system there is a behaviour that for which a customer may be used for all the partner functions explicitly. But in CRM system there is no restriction and BP may be used for all partner functions.
And the bdoc error is generated in CRM side. If you want to debug, you can stop the inbound queue of CRM then set breakpoint at the error message.
Hope I have answerred your questions.
Thanks,
Best regards,
Julin Xin