Red X Image upload. Don’t know how to fix

I’ve looked everywhere for an answer to what is probably a basic issue.
I maintain two self hosted wordpress sites. Both are built with Athalupa theme. I can upload images on mine, no issues.
My husbands only returns a box with a red X in it when I try to upload images. This morning I did manage to upload his profile pic which felt like a victory through a widget/plugin.
BUT, I cannot upload photos in entries or pages for him. They always load with a red X
example of what I’m talking about can be seen here.
http://www.robertnelsoninc.com/the-partnership/

Any help, in basic human newbie terms would be appreciated, applauded and gratefully accepted!
Rebecca