My print of the original (http://www.thingiverse.com/thing:3723) pictured on the left, failed. Slic3r 0.7.1 (installed with Pronterface) reported errors. These were fixed usinghttp://www.netfabb.com/stl_repair_fixing.php and I've published the fixed stl here to save me / you fixing it again. Fixed item is on the right).