Ecshop Vietnam Application Error

The application could not run because of the following error:

Type: E_NOTICE [8]

Message: Undefined index: promote_price in /home/xdavntes/smartphoneviet.vn/includes/lib_goods.php

Line: 668

Stack trace:

#0 /home/xdavntes/smartphoneviet.vn/includes/lib_goods.php(668): ErrorHandler->handleError(8, 'Undefined index...', '/home/xdavntes/...', 668, Array)
#1 /home/xdavntes/smartphoneviet.vn/modules/goods.php(40): get_goods_info('11')
#2 /home/xdavntes/smartphoneviet.vn/index.php(25): include_once('/home/xdavntes/...')
#3 {main}