在 Cakephp 2.1.1 稳定版本中使用 Auth 组件获得 500 内部服务器错误

我的 cakephp 应用程序 2.1.1 目前在 Cent OS 服务器上运行，每当我尝试使用 Auth 组件登录系统时，我都会随机收到 500 个内部服务器错误。

我认为这与Apache httpd.conf设置有关，所以我从无更改为AllowOverride All，但它一直在发生。

我不确定这是否与.htaccess有关，还是与Cakephp有关。

这实际上是 Cakephp 2.1.1 的错误吗？

更新 12/APR/2012

我在日志中遇到以下错误：

2012-04-11 16:26:27 Warning: Warning (512): _cake_model_ cache was unable to write 'default_ticketing_jobs_localgovstategovfedjobs' to Apc cache in [/home/commstrat2_web/html/ticket/lib/Cake/Cache/Cache.php, line 306]
Trace:
Cache::write() - CORE/Cake/Cache/Cache.php, line 306
DataSource::_cacheDescription() - CORE/Cake/Model/Datasource/DataSource.php, line 306
Mysql::describe() - CORE/Cake/Model/Datasource/Database/Mysql.php, line 334
Model::schema() - CORE/Cake/Model/Model.php, line 1281
DboSource::fields() - CORE/Cake/Model/Datasource/DboSource.php, line 2180
DboSource::read() - CORE/Cake/Model/Datasource/DboSource.php, line 1027
Model::find() - CORE/Cake/Model/Model.php, line 2635
JobsLocalgovstategovfedjobsController::index() - APP/Controller/JobsLocalgovstategovfedjobsController.php, line 38
ReflectionMethod::invokeArgs() - [internal], line ??
Controller::invokeAction() - CORE/Cake/Controller/Controller.php, line 488
Dispatcher::_invoke() - CORE/Cake/Routing/Dispatcher.php, line 103
Dispatcher::dispatch() - CORE/Cake/Routing/Dispatcher.php, line 85
[main] - APP/webroot/index.php, line 96
2012-04-11 16:26:30 Warning: Warning (512): _cake_core_ cache was unable to write 'file_map' to Apc cache in [/home/commstrat2_web/html/ticket/lib/Cake/Cache/Cache.php, line 306]
Trace:
Cache::write() - CORE/Cake/Cache/Cache.php, line 306
App::shutdown() - CORE/Cake/Core/App.php, line 884
[main] - [internal], line ??
2012-04-11 16:26:30 Warning: Warning (512): _cake_core_ cache was unable to write 'method_cache' to Apc cache in [/home/commstrat2_web/html/ticket/lib/Cake/Cache/Cache.php, line 306]
Trace:
Cache::write() - CORE/Cake/Cache/Cache.php, line 306
DboSource::__destruct() - CORE/Cake/Model/Datasource/DboSource.php, line 3148
[main] - [internal], line ??

另外，当我启用调试并尝试在浏览器上注销以下错误时：

Fatal error: Call to a member function logout() on a non-object in /home/commstrat2_web/html/ticket/app/Controller/UsersController.php on line 117

当我关闭调试时，它只是出现空白屏幕，这仅在登录和注销时发生。