I had a similar issue where when NextGen gallery was activated (NextGen Pro was not a factor), all of my front-end links were resolving back to the homepage when using the permalink structure /%postname%/ oddly enough the default permalink structure setting is a work around, but not a good SEO practice. I believed this was caused by me removing the “Permalink slug” value of “nggallery” – /wp-admin/admin.php?page=ngg_other_options.
When I went to edit/save anything under “Other Options” after removing this value within the NextGen gallery setting, it would no longer save my revisions and then began redirected me to the homepage.
SOLUTION: What I did to resolve the issue is remove the set values in the wp_options table in the WordPress database under “wp_ngg_options”. Be sure to backup your database before hacking away like I did to find the issue.
This resolved the issue and only required me to once again update my “Other Options” setting which was a snap!
