Idoc fails with error "Contact 000XXXXX is linked to a sales contact"

Hi Gurus,

I have debugged a little and found that this error comes after the function module but i can not figure out why.Error message number : F2779

IDOC_MANUAL_INPUT.

Below is the source code.

CALL FUNCTION 'IDOC_MANUAL_INPUT'

           EXPORTING

             idoc_number      = t_edidc-docnum

             input_exception  = input_exception

             no_dialog        = p_wodial

           EXCEPTIONS

             no_authorization = 1

             OTHERS           = 2.

         IF sy-subrc IS NOT INITIAL.

           MESSAGE ID sy-msgid TYPE 'S' NUMBER sy-msgno

                   WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.

         ENDIF.

Please Help.