php files not loading

[inoculatedmind]

Hello, I'm a newcomer to these forums. I just got a VPS with plesk installed, and am running several websites on it. All of a sudden, though, one of my websites, which has a wordpress blog on it, stopped working. Whenever you go to my homepage, http://www.inoculatedmind.com , you're treated with a blank screen. I entered the url for a few files, though, and it appears that almost everything loads fine:
http://www.inoculatedmind.com/index.html - html works
http://www.inoculatedmind.com/construction.jpg - pics work
http://www.inoculatedmind.com/audio/mindcast.xml - xml podcast feed works.
So I've narrowed it down to the php files not loading. I checked my settings for the site, and "php support" is checked, along with safe mode (unchecking this didn't change anything), and support for all the other stuff is also checked. I compared the settings of this site with one of the other ones I run on the server,
http://www.sociologique.org - and they are identical in settings, yet, are behaving differently.
Any php page I try to bring up ends in a blank browser.

Does anyone have any ideas about what I should do to fix this?