Yeah I see the typo in Michael's old upgrade for 2.8 it should be showgallery.php
// Files no longer needed
unlink( "$RP_PATH/showcat.php");
well I for new users who download I also placed the alter table to add thumbnails in the 2.9 upgrade so user's did not need to run the old upgrade to correct a past mistake in the upgrade process. The worst someone can have now is a mysql already entered error