Discuz! X3.2升级出现错误，怎么排除原因？

Warning: include_once(../source/class/class_core.php) [function.include-once]: failed to open stream: No such file or directory in /www/users/cfcf.cn/install/update.php on line 10

Warning: include_once() [function.include]: Failed opening '../source/class/class_core.php' for inclusion (include_path='.:') in /www/users/cfcf.cn/install/update.php on line 10

Warning: include_once(../source/function/function_core.php) [function.include-once]: failed to open stream: No such file or directory in /www/users/cfcf.cn/install/update.php on line 11

Warning: include_once() [function.include]: Failed opening '../source/function/function_core.php' for inclusion (include_path='.:') in /www/users/cfcf.cn/install/update.php on line 11

Fatal error: Class 'C' not found in /www/users/cfcf.cn/install/update.php on line 16