Broken Post – "phd.php missing" error message

One of my posts is generating an error message when you try to view it.
It should be here:
http://toomuchglass.net/index.php/2010/10/14/tilting-off-in-every-direction/

But when you load that, depending on what browser you use, you get some variation of a 404 Not Found error message. It exists in my dashboard just fine, and I tried “Updating” it to see it that would help but it does not. If I click “View Post” from the Dashboard I get the same 404 Error message.

If you try to view the page in Chrome, it offers to show you the cached version of the page, so it definitely worked once, and I know people looked at it with the direct link once upon a time.

If you go to the archive page for that day, it shows up as one of two posts, with a preview
http://toomuchglass.net/index.php/2010/10/14/
but if you click on the title link for the post you get the same error message.

If you try to view it in Firefox it provides the error message:

“The requested URL /home/garbows/public_html/uneven/phd.php was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.”

I searched the forum and the Internet, for “phd.php” and found nothing useful.

As far as I know, this is the only post affected. I have not checked every post on my blog, but I checked both a random sample and every post near to this one in time, and none were similarly affected.