I looked at the URL and the datatable is working (for me). It looks like a regular table but if you click the column headings, it sorts alphabetically. I’m using Internet Explorer 10.
The Infobox is behind the map, as you suspected. The theme must apply a z-index somewhere. You can either remove it from the theme’s style.css or try this to raise the infobox:
You can test it using Firebug if that helps – just search for ‘map-infobox’ to find the infobox in the page HTML.