Can't install WPMU DEV Dashboard

Getting the following error when accessing the Upload Plug-In area:

Server error
The website encountered an error while retrieving http://www.dailyhealthfix.com/wp-admin/plugin-install.php?tab=upload. It may be down for maintenance or configured incorrectly.
Here are some suggestions:
Reload this webpage later.
HTTP Error 500 (Internal Server Error): An unexpected condition was encountered while the server was attempting to fulfill the request.

What do you recommend I do?