Next Generation Gallery , Tags showing 404 error

Hi I was recently installed Next generation Gallery Plugin in my site : https://theaterbalcony.com

Gallery I have posted into new posts and is working fine. However for each photo I created couple of galleries, however today in google webmaster tool I got more than 50 404 errors for those tags.

The post which I embed the gallery : https://theaterbalcony.com/2012/11/06/dracula-3d-stills-and-poster-gallery/

Examples of urls where I am getting 404 errors,

1. https://theaterbalcony.com/ngg_tag/dracula-3d-actress-in-mundu/
2. https://theaterbalcony.com/ngg_tag/dracula-3d-actress/

and for all other tags which I have added.