Brilliant theme and by far the most configurable at wordpress.org! My mate is very pleased with the website I've just put together for him.
My problem: when I type in a non-existent url I get the 404 page but I also get a lot of what looks like php, css and html. Have a look at http://www.ashleytempestengineering.com/id2.html and you'll see what I mean.
If I set my permalinks to 'default' I get the standard browser '404 page not found' message.
When I set my permalinks to Month and name (/%year%/%monthnum%/%postname%/) I get the page showing the script as above.
I'm using Linux at the UK Fasthosts if that is any indication. I'm a bit stuck with what to do so if anyone can offer a suggestion I'd be very grateful.