Matt,
Thanks for reaching out and sorry to hear you’re having issues. This looks like one of two things, either a plugin conflict, or an issue with your theme.
I would try resolving these JS errors in your theme and see if that fixes the issue: http://d.pr/i/O99T
Also, have you tried reverting to the default Twenty Eleven theme? If you’re getting the same results with the Twenty Eleven theme, then we can narrow it down to a plugin conflict. If it does work under Twenty Eleven, then we know it must be a theme issue.
Try those suggestions and let me know if that resolves the issue. Thanks!