Don’t know if this’ll help you, but I also ran into a problem where any new gallery NextGen made had the wrong permissions.
I realized it was b/c I had SSH’d onto my server & injudiciously changed the permissions of wp-content/gallery itself at a previous time. This caused NextGen to create galleries with wrong permissions.
Once I tried: chmod 775 /wp-content/gallery, NextGen creates directories with the proper permissions.
Cheers,
Rishi
