Re: WordPress + bbPress Integration 101
PHP 4 users with WP 2.5.0 + bbPress 0.9.x
There is a HUGE BUG in the way the WP 2.5.0 (not 2.5.1) handles the login cookie. You won’t have a problem with PHP 5, only PHP 4.
So with PHP 4, you MUST use WP 2.5.1 and not WP 2.5.0 (aka 2.5) with bbPress 0.9 for cookie integration. Otherwise you’ll never get it to work.
There are only THREE files you need to replace in 2.5.0 to make it into 2.5.1:
function wp_hash() in WP 2.5.0 never calls hash_hmac if it doesn’t exist and just returns a plain md5 instead. This method is incompatible with bbPress 0.9 – The compatibility function in compat.php is not loaded in time.