404 Error — Please Help

We recently had a custom Joomla! 1.0 template created and installed by https://w3-markup.com. In the past, we've never had a problem with them but on this project they have been very slow and unresponsive. A major part of their service is to create w3 valid sites, however this site is displaying a "404 not found" error and they have not responded to any of our emails over the last several weeks about this. At this point, I've given up on them and am trying to figure out how to resolve this. At least, I just want to get w3 to at least read this site!?

This site is:

http://insidegrape.com/

W3 Error

Any thoughts on this would be much appreciated!

Thanks.