Odd question that I hope someone can help me with. I've been developing in PHP on my Ubuntu machine for quite some time with no difficulties. I have several applications utilizing PHP / MySql and all work perfectly. Recently I've begun working with the Yii framework ( don't worry, this isn't a Yii question ). The framework requires php PDO in order to work with MySql. So, I run php -i|grep PDO and sure enough it is enabled. When I installed the framework I did a requirements check and it threw a warning re: the PDO. It didn't list it as a fail, just a warning. Anyway, as I begin trying to access MySql from the Yii framework I get a PDO unable to open stream error. I'm confused here. PDO is indeed enabled. It's there. The Yii site I'm working on is in the same path as all of my other sites. Yet.... no PDO. Any pro tips out there?