I had the same blank page problem with 2.6.5. I figured out that setting my wp-config.php chmod to 600 from my system default of 644 to better secure the db info causes blank pages everywhere (I’m running Solaris 10). So I tried 640 and the change immediately fixed my problem: all pages re-appeared. So I created a new group that only contains my wordpress system user and I’m ok with that. Hope this helps.
