Careful, lotsa errors:
Looking at your 'supposedly_clean' theme up now and I don't see anything else unusual. My Apache and php versions are the same as yours (no problem there). I am disappointed the current theme uses @import for your style sheet, but I imagine with all the themes you've tested that can't always be the case. (For reference, I recommend a link, it gets more precedence, e.g.;
<link rel="stylesheet" title="supposedly_clean" href="<?php bloginfo('stylesheet_url'); ?>" type="text/css" media="all" /> ).
The only other thing I can suggest is having http://install4free.wordpress.com/ do a new install. If they run across the same issue they will have the access necessary to troubleshoot/address it.