使用Yii来建立博客（第二阶段）视频的问题 [ 新手入门 ]

修改到了POST rules检测部分， 地址栏输入blog/r=post进入post页面 点右侧create post进入创建post页面 点击下面create按钮 出现500错误。

Server error
The website encountered an error while retrieving http://localhost/blog/index.php?r=post/create. It may be down for maintenance or configured incorrectly.
Here are some suggestions:
Reload this webpage later.
HTTP Error 500 (Internal Server Error): An unexpected condition was encountered while the server was attempting to fulfill the request.

求解释