Blank screen appearing on Customize screen

I have uploaded the latest version of the free version of Jomsom theme through the WordPress admin uploader. The default theme appears to load on the site just fine, but when I try to access the Appearance > Customize section I just get a blank screen. The left column to navigate customization options is there -- but nothing is in it that I can select for customization. The wider preview section on the right is completely blank. I am running the latest version of WordPress. The domain is http://www.bigyellowsticky.com