phpBB, "Could not get style data"

My phpBB forum, set up through “One-Click Installs”, stopped working over night, without me doing anything. “General Error Could not get style data”.

http://forum.lightheadsw.com/

What can I do to fix this?

Check all the files got transferred correctly. There should be nearly 100 items in /styles/prosilver/template

Also check the above folder has suitable chmod permissons