No Themes will Install

Hello,

I’m unable to install any new themes through wordpress admin page. When I try installing one through the wordpress director of themes, I enter my host server info, it processes and then loads a blank page. The theme doesn’t show up on my themes page. If I try uploading a .zip file manually, it says: 500 – Internal server error.
There is a problem with the resource you are looking for, and it cannot be displayed. I’ve tried multiple times and with multiple themes.

Does anyone know what’s going on? If it helps, I’m using Godaddy as my host and using Safari, but it also doesn’t work with Firefox.

Thanks for the help.