In the Yii entry script, you need to commend the following lines
<?php
// comment out the following two lines when deployed to production
defined('YII_DEBUG') or define('YII_DEBUG', true);
defined('YII_ENV') or define('YII_ENV', 'dev');
so that it will be
<?php
// comment out the following two lines when deployed to production
//defined('YII_DEBUG') or define('YII_DEBUG', true);
//defined('YII_ENV') or define('YII_ENV', 'dev');
now you will not receive the trace levels of errors.
And based on the settings you have given in your php.ini configuration file, you can see the php errors.