stone age theme causes problem on drop.org

after switching my theme to "stone age" on drop.org, i get the following message whenever i try to access a page on that site while logged in:

Fatal error: Cannot instantiate non-existent class: theme_stone age in /var/www/drop.org/includes/theme.inc on line 82

(the message appears whether i use mozilla and lynx)

(Perhaps this isn't the appropriate place to report a drop.org specific bug -- i was referred here by www.drop.org/node.php?id=162)

thanks