I have exactly the same problem as mentioned in http://ww.wp.xz.cn/support/topic/plugin-nextgen-gallery-error-404-not-found-gallery-in-album-view?replies=6
But the solution given there is to link to a page. This is a workaround as it is expected that a lightbox effect will be displayed when no link to page is explicitly assigned. however I must add this 404 error ONLY occurs while suing the CRIUS Theme. The default themes work fine.
What works on CRIUS theme:
If i create a gallery, it displays all photos in a gallery in a row (works fine)
What does NOT work with CRIUS theme:
When I add an album and the shortcode [album id=1 template=extend], the page displays the album containing 6 photos and when I click on the album it loads a page with 404 error.
I have tried permalinks etc but no soultion at all while in CRIUS theme.
thanks in advance