The Geeklog/Gallery integration package has just been updated. John Hughes noticed that the gallery integration package was missing an update to the util.php file. There's a change to util.php that is necessary to allow mod_rewrite while inside Geeklog. Gallery turns off mod_rewrite if it is wrapped in anything. This is because Nuke doesn't allow it.
You can download the updated package here. Note, if you are upgrading simply replace util.php in /path/to/gallery.
Thanks John!