failed theme install screwed up my whole site

I installed this theme via zip because it wasn't installing from my wpmu dash and now every link I click on gives me this page

Fatal error: Call to undefined function wp_normalize_path() in /hermes/walnaweb02a/b1463/moo.strommovementintegra/fit/wp-content/themes/upfront/library/servers/class_upfront_admin.php on line 28.

I can't allow access for someone to work on it because I can't get onto any of my pages or links