capsizeking

Hi guys, So I'm trying to 3d print just a stock craft, however when I go into the submenu and select 'Make 3D Printable' I obtain the following error: http://imgur.com/ALMjeal Any help will be gratefully appreciated (ps. also having trouble with the textures however this isn't so important as i am going to paint, it'd just be a little nicer to work with)