CRM_PARTNER_READ_OW returns exception

[ntoar]

Hello experts,

I am getting partner's information using :

 APPEND iv_guid TO lt_header_guid.
    CALL FUNCTION 'CRM_ORDER_READ'
      EXPORTING
        it_header_guid       = lt_header_guid
      IMPORTING
        et_partner           = lt_partner
      CHANGING
        cv_log_handle        = lt_log_handle
      EXCEPTIONS
        document_not_found   = 1
        error_occurred       = 2
        document_locked      = 3
        no_change_authority  = 4
        no_display_authority = 5
        no_change_allowed    = 6
        OTHERS               = 7.


  "Get partner info
        CALL FUNCTION 'CRM_PARTNER_READ_OW'
          EXPORTING
            iv_ref_guid          = lv_bp_partner_guid
            iv_ref_kind          = 'A'
            iv_partner_fct       = '00000002'
*           IV_PARTNER_PFT       =
*           IV_PFT_SUBTYPE       =
*           IV_MAINPARTNER_ONLY  = ' '
*           IV_GET_BP_NUMBERS    = ' '
*           IV_REFRESH_ADDRESS_REF             = ' '
          IMPORTING
            et_partner_wrk       = ls_partner_wrk
*           ES_PARTNER_WRK       =
*           ES_MORE_THAN_ONE_MAINPARTNER       =
          EXCEPTIONS
            error_occurred       = 1
            parameter_error      = 2
            entry_does_not_exist = 3
            OTHERS               = 4.

But CRM_PARTNER_READ_OW ends with an exception. Neither I can do an F5 to go into the function module and debugg it.

Do any of you know what could be the issue?

Many thanks.

Kind regards.