Weird: New Image Gallery Vocabulary shows up after upgrade --- After upgrade from 4.7 to 5.0

Hello,

My upgrade from 4.7 to 5.0 went awry when I noticed none of the dozen or so image galleries show up anymore: http://projectharambee.org/help_africa_aid/image

Upon checking the Categories page, I realized the system had created a new and identical image gallery vocabulary, like it would by default in a new installation to enable image galleries.

See screenshot: http://picasaweb.google.com/saneplanet22/Misc#5245304808618622066

The new vocab doesn't contain any terms.

And it won't delete! When I delete it, I get the confirmation: http://picasaweb.google.com/saneplanet22/Misc#5245305817580486626

But the category either stays or returns on its own moments later.

Is the solution deleting the category in database ? How ?

And if I'm successful, would system start recognizing the old new image galleries category?

I can't figure out why all this happened. I know the image gallery on this site saw some unusual treatment. The person using it, for example, was putting in huge, page-long text in the DESCRIPTION field of each image gallery, forcing me to use CSS overflow selector to keep the design in tact. The system should've had a validation to put a limit on field size, but I've also learned my lesson about not letting just anyone admin Drupal.