Hi Siva,
There error will generated from standart function module BBP_PARTNER_FUNCTION_EXISTENCE, where lt_partner_card should be filled with business partners with object type. If there is any failure in filling of partner details into lt_partner_card there error you have mention will be generated.
Please check if there is any enhacement done in this particular FM which restricted the updation internal table lt_partner_card.
Thanks ,
Anuraj