No Category Page for Gallery Theme

Hi all,

I think I have messed something up but I can't figure out what. On one of the sites in my multisite network, the Gallery Theme is used and most everything works fine except sitename.com/category where it says "Page Not Found." I have tried to reset parmalinks but that did not fix it. I am not using a separate template for the category, I was planning to just use the index template.

Any thoughts?