oracle - Oracleで「無効な列インデックス」エラーが発生する

Question

Oracle の次のコードで無効な列エラーを取得しています。しかし、カーソルに割り当てられたクエリを個別に実行すると、問題なく動作します。私がやっている間違いを教えてください：

CREATE OR REPLACE PROCEDURE etl_mergeEmployeeAttendee
(
  v_EmployeeNumber IN VARCHAR2 DEFAULT NULL ,
  v_AttendeeName OUT NVARCHAR2,
  v_EmployeeAttendeeId OUT NUMBER,
  v_AttendeeTitle OUT NVARCHAR2,
  v_Company OUT NVARCHAR2,
  v_Relationship OUT NVARCHAR2,
  v_Operation OUT NUMBER,
  v_Error OUT NUMBER
)
AS
  v_Employee_AttendeeId NUMBER(10,0);
  v_Employee_Id NUMBER(10,0);
  v_Attendee_Name NVARCHAR2(50);
  v_Attendee_Title NVARCHAR2(50);
  v_Com_pany NVARCHAR2(50);
  v_Relation_ship NVARCHAR2(50);

  CURSOR sel_prod_attendee_csr
     IS SELECT a.EmployeeAttendeeId ,
          a.EmployeeId ,
          a.AttendeeName ,
          a.AttendeeTitle ,
          a.Company ,
          a.Relationship 
        FROM EmployeeAttendee a,
             Employee b
        WHERE b.EmployeeNumber = v_EmployeeNumber
          AND a.EmployeeId = b.EmployeeId;

BEGIN
  OPEN sel_prod_attendee_csr;
  FETCH sel_prod_attendee_csr INTO
    v_Employee_AttendeeId, v_Employee_Id,v_Attendee_Name,v_Attendee_Title,v_Com_pany,v_Relation_ship;
  IF sel_prod_attendee_csr%FOUND= true THEN

    /* found */
    BEGIN
      v_Operation := 1 ;
      v_AttendeeTitle := v_Attendee_Title ;
      v_Company := v_Com_pany ;
      v_Relationship := v_Relation_ship ;
      v_AttendeeName :=v_Attendee_Name;
    END;
  ELSE
    v_Operation := 2 ;-- Insert
  END IF;
  CLOSE sel_prod_attendee_csr;
END;