The trouble starts at line 78 of your generated HTML, where you close a
list-item that wasn’t opened. Furthermore, you seem to be using some kind of plugin that is adding extra tags to the gallery and basically making the entire HTML invalid. (attributes not closed with ” and such.)
I saw you are using something called PageLines, this framework (or theme or plugin or script or whatever it is) modifies the entire HTML structure. My guess is you will have a lot of issues with other plugins too if you keep using this.
I’ll try to install PageLines to see what is does and see if I can figure something out.