Links Don’t work and Disappear

I am using twenty ten theme with everything updated. It is located at http://kbfarl.com. I am having a problem with my ‘listings’ page. The pdf’s will not show up when clicked on. I get the message: “Not Found, Apologies, but the page you requested could not be found. Perhaps searching will help.”
When I edit the page link there is nothing there. So, I paste the link url back but they are not there after I update. Also when I click to ‘view’ the pdf in Media I get the error: ?attachment_id=1114.
I have de-activated and re-activated the plugins: ‘Open external links in a new window’ and ‘page links to’.
Thanks!