DataSet 写入到Excel文档中的问题

Code:/// <summary>
        /// Write DS to excel file
        /// </summary>
        /// <param name="Path"></param>
        /// <param name="oldds"></param>
        public void DSToExcel(DataSet oldds)
        {
            string strCon = "Provider=Microsoft.Jet.Oledb.4.0;Data Source=" + _path2 + ";Extended Properties='Excel 8.0;HDR=Yes;IMEX=1;'";
            OleDbConnection conn = new OleDbConnection(strCon);
            OleDbCommand cmd = null;            try
            {
                conn.Open();                //cmd = new OleDbCommand("create table [sheet3]([parameterID] Text,[parameterName] Text,[Description] Text)", conn);
                //cmd.ExecuteNonQuery();                string strSql = "INSERT INTO [Sheet3$] ([F1], [F2],[F3]) VALUES (?, ?, ?)";
                cmd = new OleDbCommand(strSql, conn);                // Add parameters
                for (int i = 0; i < 3; i++)
                {
                    cmd.Parameters.Add(i.ToString(), OleDbType.VarChar);
                }                // Add values to parameters
                foreach (DataRow row in oldds.Tables[0].Rows)
                {
                    for (int index = 0; index < cmd.Parameters.Count;index++ )
                    {
                        cmd.Parameters[index].Value = row[index].ToString();
                    }                    // Insert values into the table
                    cmd.ExecuteNonQuery();
                }
            }
            catch (System.Exception e)
            {            }
            finally
            {
                // Release resources
                if (cmd != null)
                {
                    cmd.Dispose();
                }
                conn.Dispose();            }
        }
    }
Create Table报错：不能修改表 'sheet3' 的设计。它在只读数据库中。Insert报错：操作必须使用一个可更新的查询。各位高手帮忙啊！