Yeah, that error is because there is no picture folder associated with the database you are using. I had that problem, it does explain how to fix this in the "3 step walk through" the game gives you when you click the "install a mod" button under the editor page from the basic start page. I also copied some of the picture files over from the original database that I liked and put them as "user" names so I could use them in the Marvel world.
And yes Lazorbeak, I am loving it!