Genesis Menu Error

Why do I keep getting a Server Error when trying to update my drop-down menu on this website http://www.dwuathletics.com/.

Under Baseball there are 2 “Stat” options that need to be deleted. “Baseball stats is the correct link, but every time I try to delete the other two, I get this error.

“Server error
The website encountered an error while retrieving
http://www.dwuathletics.com/wp-admin/nav-menus.php. 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. “

PLEASE HELP; I NEED TO GET THIS FIXED!