Bdoc erro with groupware integration

Hi Friends,

I am getting failed bdocs those are relevant to groupware entries and below error messages in SMW01 for the same, it's happening sometimes. Please help me why its happening and how to resolved it as I do not have much experience on this groupware concept.

-Partner data processed with key PartnerGUID 0

-Enter at least one number for the business partner

-Validation error occurred: Module CRM_BUPA_MAIN_VAL, BDoc type BUPA_MAIN.

Thanks and Regards,

VR