我正在尝试从我的代码创建sql服务器备份并执行该操作。但是当Path是  在驱动器C中：（例如：文档或桌面）无法创建备份。怎么了？

try
            {
                string DES = GenerateBackupLocation(Destination);
                string databaseName = "MyDataBase";
                Backup sqlBackup = new Backup();
                sqlBackup.action = BackupactionType.Database;
                sqlBackup.BackupSetDescription = "BackUp of:" + databaseName + "on" + DateTime.Now.ToShortDateString();
                sqlBackup.BackupSetName = "FullBackUp";
                sqlBackup.Database = databaseName;
                BackupDeviceItem deviceItem = new BackupDeviceItem(DES + "\\" + databaseName + ".bak",DeviceType.File);
                SqlConnection con = new SqlConnection(Connectionstring);
                ServerConnection connection = new ServerConnection(con);
                Server sqlServer = new Server(connection);
                sqlServer.ConnectionContext.StatementTimeout = 60 * 60;
                Database db = sqlServer.Databases[databaseName];
                sqlBackup.Initialize = true;
                sqlBackup.Checksum = true;
                sqlBackup.ContinueAfterError = true;
                sqlBackup.Devices.Add(deviceItem);
                sqlBackup.Incremental = false;
                sqlBackup.ExpirationDate = DateTime.Now.AddDays(3);
                sqlBackup.LogTruncation = BackupTruncateLogType.Truncate;
                sqlBackup.FormatMedia = false;
                sqlBackup.SqlBackup(sqlServer);
                sqlBackup.Devices.Remove(deviceItem);
                Message = "Backup Ok";
            }
            catch
            {
                Message = "Can't Create Backup";
            }