Authors Intentions

Okay, this is a serious question for me... A number of different posts recently have gotten quite seriously into Dramatic Theory, and one thing that keeps popping up is "The Author's Intention". Now, when I was younger I had Roland Barthes' theory of "The Death of the Author" drummed into me. To try and put it simply - The meaning of any work of art or literature is the meaning that the reader/watcher gets from it, and any interpretation is valid as long as the text bears it out, and what the author originally intended is largely irrelevant... (My apologies if I put it clumsily, it WAS YEARS ago) But this was a literary/philosophical theory, not a purely dramatic one. My question is: Has Roland Barthes been thrown out and someone forgot to forward me the memo? or, As his theory is a general literary theory not a specific dramatic one, has it just not filtered through to the performing arts? Can't say I'm losing sleep over it or anything, but it has piqued my interest :-)