The first thing I would do if you can't access wp-admin would be to FTP in and delete any recent plugins in the wp-content/plugins as Lynn suggests.
You have whitespace at the top of your source code so that is most likely causing the problem. Something you did inserted whitespace at the top of header.php or functions.php, most likely the plugin.
If removing the plugins doesn't work, unzip Socrates on your desktop and then reupload the functions.php and header.php file to /wp-content/themes/socrates/
If that doesn't work delete the socrates folder.
That will default your blog to the twentyten theme, and then you can reinstall Socrates 2.2.14 via the dashboard.
The fact that it works without www is very odd.
I noticed that you already opened a ticket on wordpress.org as well.
I'm 99.9% sure this is not a Socrates issue, but a plugin issue or the editing of one of our templates to leave whitespace. So if you get this resolved I'd appreciate it if you'd would reply to that thread that it's resolved.
Also, this is the "please read first" thread. We have support threads where you can post your questions in the future.