I have searched but not found a viable solution to this issue. The galleries inside an album go to a "page not found" page all of a sudden. I made a brand new gallery and album to see if it was a problem with my pre-existing galleries. (it wasn't)
I tried resetting the plugin. So far I have turned off and on permalinks and Deactivate gallery page link. I am using the Backstreet Template and when I switched over to a basic default theme it worked so there appears to be a conflict somewhere.
The only solution I have found is to have the galleries link to another page and that is not acceptable as we have far too many galleries to deal with. The gallery page is here - http://www.sethgrabel.com/galleries-2/
Anyone have any ideas?