连阴雨啊……1.5.0 RC1升级到1.5.1又出问题了

从本站下载了1.5.1的升级包之后，直接覆盖我的1.5.0，再登录站点，发现前后台都打不开了
前台说：
Warning: require_once(/……path……/libraries/joomla/import.php) [function.require-once]: failed to open stream: No such file or directory in /……path……/includes/framework.php on line 42

Fatal error: require_once() [function.require]: Failed opening required '/……path……/libraries/joomla/import.php' (include_path='.:/usr/share/php:/usr/share/pear') in /……path……/includes/framework.php on line 42

后台说：
Fatal error: Call to undefined method JFactory::getapplication() in /……path……/administrator/index.php on line 33

请各位帮忙给看看怎么办呢？

1.5感觉目前还是很不稳定,装了测试了5、6次,最终还是放弃了