Cakephp 2.1.1 auth APC缓存错误

I'm getting below error when trying to log into Cakephp app.

Warning (512): _cake_model_ cache was unable to write 'default_ticketing_tickets' to Apc cache [CORE/Cake/Cache/Cache.php, line 306]

This happens on random occassions and I cannot find out why.

I have enabled the tmp folder, files and subfolders to 777

Is there something else I need to do as it's still not working?

This is on Cent OS server

UPDATE: Below is what I am getting under error message.

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
FormHelper::_introspectModel() - /home/commstrat2_web/html/roadconference/lib/Cake/View/Helper/FormHelper.php, line 191
FormHelper::create() - /home/commstrat2_web/html/roadconference/lib/Cake/View/Helper/FormHelper.php, line 444
include - APP/View/Users/login.ctp, line 3
View::_evaluate() - /home/commstrat2_web/html/roadconference/lib/Cake/View/View.php, line 908
View::_render() - /home/commstrat2_web/html/roadconference/lib/Cake/View/View.php, line 872
View::render() - /home/commstrat2_web/html/roadconference/lib/Cake/View/View.php, line 463
Controller::render() - /home/commstrat2_web/html/roadconference/lib/Cake/Controller/Controller.php, line 962
Dispatcher::_invoke() - /home/commstrat2_web/html/roadconference/lib/Cake/Routing/Dispatcher.php, line 110
Dispatcher::dispatch() - /home/commstrat2_web/html/roadconference/lib/Cake/Routing/Dispatcher.php, line 85
[main] - APP/webroot/index.php, line 96