新手求教个安装老是报错的问题，我快崩溃了?报错

求各位大大帮忙，我快崩溃了，装了几次了，现在这个问题究竟是怎么回事呢？我实在搞不明白，说是那个文件问题但是应该如何解决呢？magento版本是最新的1.90

Error in file: "D:\Program Files\xampp\htdocs\magento\app\code\core\Mage\CatalogRule\sql\catalogrule_setup\upgrade-1.6.0.2-1.6.0.3.php" - SQLSTATE[42S21]: Column already exists: 1060 Duplicate column name 'sub_discount_amount' Trace: #0 D:\Program Files\xampp\htdocs\magento\app\code\core\Mage\Core\Model\Resource\Setup.php(645): Mage::exception('Mage_Core', 'Error in file: ...')
#1 D:\Program Files\xampp\htdocs\magento\app\code\core\Mage\Core\Model\Resource\Setup.php(437): Mage_Core_Model_Resource_Setup->_modifyResourceDb('upgrade', '1.6.0.2', '1.6.0.3')
#2 D:\Program Files\xampp\htdocs\magento\app\code\core\Mage\Core\Model\Resource\Setup.php(320): Mage_Core_Model_Resource_Setup->_upgradeResourceDb('1.6.0.2', '1.6.0.3')
#3 D:\Program Files\xampp\htdocs\magento\app\code\core\Mage\Core\Model\Resource\Setup.php(235): Mage_Core_Model_Resource_Setup->applyUpdates()
#4 D:\Program Files\xampp\htdocs\magento\app\code\core\Mage\Core\Model\App.php(417): Mage_Core_Model_Resource_Setup::applyAllUpdates()
#5 D:\Program Files\xampp\htdocs\magento\app\code\core\Mage\Core\Model\App.php(343): Mage_Core_Model_App->_initModules()
#6 D:\Program Files\xampp\htdocs\magento\app\Mage.php(684): Mage_Core_Model_App->run(Array)
#7 D:\Program Files\xampp\htdocs\magento\index.php(87): Mage::run('', 'store')
#8 {main}