Server at WP-Admin can't be found to upload custom header

I originally installed my WP in a folder called Blog. Today I moved my WP folders and files to my root folder public_html at StephieSmith.com. (Some of my pages are not in WP right now and may never be because I need some to expand to full width, but want to keep others at 940 pixels and I couldn’t see a way to do that.)

I changed the URIs, changed the config.sys file, changed the menu. I noticed that my images had disappeared, so I reinserted them. Everything seems to work, EXCEPT when I try to upload my custom header again (it disappeared), I get this message:
“This webpage is not available. The server at wp-admin can’t be found, because the DNS lookup failed.”

I’m sure there must be some code that still needs changing, but I can’t find this exact problem stated anywhere else. I can log into my WP-Admin, add pages, posts, menu items, etc., and it all shows up on my website. Occasionally I get that message when I apply a change, but when I go back and look, the change did get made…EXCEPT when it comes to this custom header. Also, I have to log in with my password every time with every browser (I have IE, Firefox and Chrome) even tho I tell it to save the password, which always worked previously. Plus I had to reset the password for each browser the first 2 or 3 times I used it this morning.

I see that if I click on the missing header image x on my website, it gives me the old path stephiesmith.com/blog/header200.jpg. I have uploaded via FTP the header jpg to all the image folders, and other folders as well. I can’t figure out what I’m missing and I’m afraid to upgrade to 3.2 while this problem is going on.

Any ideas?