[chrishajer]

This problem has come up a couple times in the past couple days:

https://bbpress.org/forums/topic/bbpress-10-alpha-6-released#post-22750

The function do_action exists in ./bb-includes/wp-functions.php. Do you have that file and is it complete? Is there a line (around 641, in 0.9.0.4 anyway) that starts with:

function do_action ($tag, $arg = '') {

Is it possible that not all the files were properly uploaded?