Pager missing on some albums

On some of the albums on my site, the pager for individual photos is missing for anonymous users. The pager for the album thumbprints is there. If I login, then the pager for individual photos appears. The results are the same using Firefox3 or IE7.

I can't find anything different in the configuration of the albums, and I created the albums with the root account. Some albums had photos uploaded by various people, and some only by root, but the appearance of the pager seems to be random, as these variations don't determine when the pager appears.

You can see the albums at http://www.fumcsantarosa.org/albums
An example of an album where paging is missing is http://www.fumcsantarosa.org/album/2009-gawthrop-festival-concert-photos
An example of an album where paging is present is http://www.fumcsantarosa.org/choirtour2008