I think this is an issue with the Boilerplate theme I am using as I have deactivated all my plugins to see if that made a difference but it has not.
I have installed MapPress as well as 10s of other Google Maps plugins previously and it seems that something is stoping the JS involved in loading the map. I have had a similar issue with Simple Modal Contact Form. Basically, the shortcode works and the mark up can be seen in the source but no sign of the map.
I have custom JS working fine. Can you see or think of any reasons why this may happen?
Here is a link to the site... http://infinity.iamphiljames.co.uk/