Can’t upload images to Media Library

I had my site at a free web host and the email wouldn’t work. I tried to move it to a paid host but it wouldn’t migrate because supposedly there were empty tables in my database. So now I’m trying to start my site over from the beginning. And there are still problems.

At first, when I tried to upload images to the Media Library, I was getting grey squares instead of images. Now I’m not even getting those; instead I’m getting an error message: “Internal Server Error / The server encountered an internal error or misconfiguration and was unable to complete your request. / Please contact the server administrator at webmaster@(mydomain) to inform them of the time this error occurred, and the actions you performed just before this error. / More information about this error may be available in the server error log. / Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.“

The page I need help with: [log in to see the link]