no closing html tag on home page

I have just taken over doing website maintenance for a new client. She went to the website: ismyblogworking.com. And it is saying your page is missing the closing html tag. So I went to her site, and clicked view page source, and indeed there is not a closing html tag.

This a custom theme, in which she cannot contact the designer. The settings are set to view latest post, so the home page is not a created page. The site was done in 2010. I have searched the files in the hosting. How can I find the code for the home page to add the closing html tag? Or is it not a problem?

The website is http://frenchiepuppies.com