Loading the database library causes a freeze

[eluser]elverion[/eluser]
I'm working on another site using CodeIgniter (I've used CI plenty in the past without this issue), and am just about to begin working on the database side of things. I've added 'database' to the autoload config, but now upon trying to load any page, it just appears to continue loading for about 30 seconds before giving up and leaving the page completely blank. The same thing happens when I instead use $this->load->database() in a controller. As best as I can tell, the freeze happens within the database driver; specifically when trying to connect() or pconnect().

I've completely reinstalled Apache, PHP5, MySQL server, and CodeIgniter but the problem persists. All available logs contain no errors or any useful information what-so-ever. Any clues on where to even begin diagnosing the problem?