Hi Phil,
I lost all my folders from my server the other day due to a dodgy script I wrote (idiot I know) I have now re-installed the theme but I am having a very strange issue.
When I first go on to the site everything looks fine until I click on a category and and the page loads but the categories ten disappear completely from the side bar. Also if I click on all categories the page is blank.
I tried clearing the template cache, which I thought worked as the categories re-appeared until I click on another cat and we are back to the missing cats again.
Here are some pictures to explain.
First enter the site
http://www.1guyseo.com/images/1.jpg
click on a category (notice the cats are gone now)
http://www.1guyseo.com/images/2.jpg
Click back to home page (cats still gone)
http://www.1guyseo.com/images/3.jpg