"Freaking"? "Damn"? :) Are you OK, mate? It's only two words. :)
There is a fairly simple reason - it's a set adverbial phrase, and answers the question "where"? There are quite a few of these in English ("at war" also comes to mind). In cases like this, you definitely don't add an article - no need to fiddle with adverbs; specifically, don't treat them like nouns.