nggallery with Atahualpa using 2.9.1, URL fails to show full picture

I am using WP 2.9.1 with Atahualpa and am having problems with the nggallery plugin when displaying full sized pictures from the galleries.

The gallery thumbnails show up fine, however when I click on the thumbnail to show the picture it fails. I have over 8000 pictures on this site and really like nggallery and do not want to change.

when I click on one of the pictures in the Album (https://www.loztom.com/blog/nggallery/page-465/album-7/gallery-131), the link fails and resolves to (https://www.loztom.com/blog/nggallery/page-465/album-7/gallery-131/image/5429).

I have checked the files are still there, have not changed any of the files, have recently upgraded to 2.9.1.

Am novice and not coder .. Is anyone able to help !! P.L.E.A.S.E !!