Site turned into bad code

I uploaded a new theme (atahualpa) and all of a sudden my entire site shows only:

Warning: include_once(/home/megwit1/bestoffates.com/wp-content/themes/atahualpa/functions/bfa_theme_options.php) [function.include-once]: failed to open stream: No such file or directory in /home/megwit1/bestoffates.com/wp-content/themes/atahualpa/functions.php on line 65

et cetera

when I go to https://www.bestoffates.com/wp-login.php the login box shows up, but once I log in it goes away and only the code shows up.