Hmmm. They say talking to oneself is one of the first signs of insanity…
I just found a year old thread on this topic: https://bbpress.org/forums/topic/bbpress-wordpress-mu-or-not-leads-to-404-errors-but-pages-still-load?replies=7#post-14899
So I have a couple of questions for anyone out there:
1. Aside from the ugliness of a core hack, is there any reason my workaround is a bad idea?
2. Has anyone produced a plugin that implements Beau’s idea in the thread above?
Sounds like there are a lot of people with deep integration, so I find it really strange that this is still a problem in WPMU 2.8.4a / bbPress 1.0.2.
Which pages are you getting the 404 header on? I just crawled my local copy quickly with firebug and was getting 200’s across the board. I’m probably missing a few of the pages though, I just loaded it up and started clicking away. 
All of them. Any bbPress page.
What versions of bbPress and WPMU are you running? Do you have BuddyPress installed?
µ 2.8.4a and bbPress 1.0.2, no buddyPress, I’m afraid that bug has yet to bite me. Maybe that narrows down the cause though?
And it definitely is *deep* integration, right?
If so, how do you do the deep integration – are you calling ‘wp-blog-header.php’ from ‘bb-config.php’?
It’s deep, I can access and use all my WordPress functionality. Afaik using wp-blog-header.php is deprecated for that use, I’ve been calling wp-load.php.
delayedinsanity, you beauty. As far as I can see, this is the problem. I switched to using wp-load.php and the status in the header is 202 without my hack. What’s more, it corrects this issue:
https://bbpress.org/forums/topic/wpmu-284a-deep-integration-breaks-rss-feed
Many thanks.
So to sum it up. I was previously doing the following in bb-config.php for deep integration:
require_once('/var/www/vhosts/youlookfab.com/httpdocs/wp-blog-header.php');
But it broke RSS feeds and put 404 headers in my forum pages. The following seems to solve both issues:
require_once('/var/www/vhosts/youlookfab.com/httpdocs/wp-load.php');
Is there a way to fix this without switching the include to wp-load.php?
I’m also running Buddypress and the “Buddybar for bbpress” plugin. Changing the include from wp-blog-header.php to wp-load.php seems to break the “My Account” menu in the admin bar. It seems that switching to wp-load.php makes the bbpress end unable to read $bp->bp_nav, which causes the “My Account” not to appear.
I’m running WPMU 2.8.4a, Buddypress 1.0.3, and bbPress 1.0.2.
