I am trying to setup banners on my site. They appear to be working, however I am unable to edit them from client side.

When I click "edit" on a banner, the edit screen appears, but not the image for the banner. (Using Image type banners only). I get the following error message whenever I try to save any changes:

You not have uploaded pictures, please upload picture.
The box for the image initially displays and then quickly disappears.

Can anyone offer any advice on how to correct this issue?