Default theme weirdness

I’m trying to move the a theme that I developed to another site and I’m having some issues. I developed it from the “default” theme. So it’s a modified version but when I move it I can’t view it on my new site. I doesn’t show up in the presentation tab and I have issues seeing the header image. I know wordpress pretty well and I think it has something to do with the fact that it is the default theme. Any ideas?