你好我有Cron Job的问题下面是为错误生成的日志可以解释我如何修复它吗？
Magento版本：1.9.2
1：无效的cron表达式
跟踪：
0 /home/kiabza/public_html/stage/app/code/core/Mage/Cron/Model/Schedule.php(68): Mage::exception('Mage_Cron', '1:Invalid cron ...')
1 /home/kiabza/public_html/stage/app/code/core/Mage/Cron/Model/Observer.php(184): Mage_Cron_Model_Schedule->setCronExpr('1')
2 /home/kiabza/public_html/stage/app/code/core/Mage/Cron/Model/Observer.php(146): Mage_Cron_Model_Observer->_generateJobs(Object(Mage_Core_Model_Config_Element), Array)
3 /home/kiabza/public_html/stage/app/code/core/Mage/Cron/Model/Observer.php(75): Mage_Cron_Model_Observer->generate()
4 /home/kiabza/public_html/stage/app/code/core/Mage/Core/Model/App.php(1358): Mage_Cron_Model_Observer->dispatch(Object(Varien_Event_Observer))
5 /home/kiabza/public_html/stage/app/code/core/Mage/Core/Model/App.php(1337): Mage_Core_Model_App->_callObserverMethod(Object(Mage_Cron_Model_Observer), 'dispatch', Object(Varien_Event_Observer))
6 /home/kiabza/public_html/stage/app/Mage.php(448): Mage_Core_Model_App->dispatchEvent('default', Array)
7 /home/kiabza/public_html/stage/cron.php(77): Mage::dispatchEvent('default')
8 {main}