I downloaded the latest trunk zip and there seems to be a small problem with the default theme. gallery.css points to images within a /themes/default/graphics directory that does not exist.
I have manually copied the /graphics directory into the default directory and it has resolved issues that I'd seen in the slide show functionality.
However having fixed the webserver errors there is still no 'speech bubble' icon next to the posted comments, which I assume is the reason for the: background: url('../../graphics/comment.gif') no-repeat 0 3px; line?