require_once dirname(dirname(__FILE__)) . '/wp-blog-header.php';

This should be used instead:

require_once dirname(dirname(__FILE__)) . '/wp-load.php';

What's the cleanest solution to this, for WP 2.8.6 installed in / and bbPress 1.0.2 installed in /forum/ ?

Thanks very much, indexing is vital to me.

function is_404 () {
global $wp_query;
if (preg_match('/(firstbbpressfoldername|secondbbpressfoldername)/i', $_SERVER['REQUEST_URI']))
{return true;}
else{
return $wp_query->is_404;}
}

After saving the irritating 404 issue has gone.
Regards
Zoli

Using WMPU btw

/forum/profile to /forum/profile.php and /forum/tags to /forum/tags.php

The profile and tags pages were still returning 404 headers.

<?php
/*
Plugin Name: No 404s
*/
?>

http://codex.wordpress.org/Writing_a_Plugin

function mbob_flush_rewrites() {
	global $wp_rewrite;
	$wp_rewrite->flush_rules();
}
add_action('init', 'mbob_flush_rewrites');

function mbob_add_rewrites($wp_rewrite) {
	add_rewrite_rule('forums/topic', 'forums/topic.php');
	add_rewrite_rule('forums/forum', 'forums/forum.php');
	add_rewrite_rule('forums', 'forums/index.php');
	$wp_rewrite->rules = array_merge($wp_rewrite->non_wp_rules, $wp_rewrite->rules);
}
add_action('generate_rewrite_rules', 'mbob_add_rewrites');

And I'm not getting a specific error really. Simply that when I upload no404s.php with this code to my wp-content/plugins directory, there is no listing in the Plugins tab to even activate it.

I tried creating a plugin from the code above, but I couldn't activate it. Can someone please help me with a step by step fix for a regular WP install? Gracias!

Thanks, beaulebens!

Which files should you put this code on? I am also installing bbPress on a MU WordPress. I get the same error. I thought maybe it's because of WP/MU not compatible with bbPress. I have the same install directories (WP/MU on root and bbPress on /forums/). And I am getting the same 404 error on user profile and post.

Thanks in advance

// Load WordPress so we can use the same templates.
define('WP_BB', 'true');
require_once dirname(dirname(__FILE__)) . '/wp-blog-header.php';

Symptoms: Pages load just fine, and all appears successful, but, upon further inspection, all bbPress pages actually return a 404 error in the HTML headers (you can see this using FireBug, or using a HEAD command to the page). NOTE: This will also happen if you create custom pages (not WP "Pages") that load the WordPress engine - they load fine, but actually throw a 404).

Explanation: What appears to be happening here, is that the page loads fine, because it is a real page. Internally however, WP doesn't know about this page (because it's a bbPress, or custom page), and so it assumes it's a request for a permalink that it can't resolve. Thus it throws a 404.

The internal rewrite system in WP allows you to add new rewrite rules, but appears to only like dealing with "internal" or WP-specific rules. If you add in what it refers to as "non_wp_rules", then it doesn't actually apply them (so it still throws a 404).

The FIX! on the code that I'm running, I have put the following WordPress plugin in place to add rules appropriate for my bbPress installation:

function mbob_flush_rewrites() {
	global $wp_rewrite;
	$wp_rewrite->flush_rules();
}
add_action('init', 'mbob_flush_rewrites');

function mbob_add_rewrites($wp_rewrite) {
	add_rewrite_rule('forums/topic', 'forums/topic.php');
	add_rewrite_rule('forums/forum', 'forums/forum.php');
	add_rewrite_rule('forums', 'forums/index.php');
	$wp_rewrite->rules = array_merge($wp_rewrite->non_wp_rules, $wp_rewrite->rules);
}
add_action('generate_rewrite_rules', 'mbob_add_rewrites');

NOTE: I have removed a lot of my bbPress installation as part of my integration, so I didn't require any other rules to handle things like profile pages or tags - you probably will need to add them if you use those features.

Hopefully this will help someone else and prevent you from beating your head against a wall like I almost did :)

Thanks to sambauers for helping me out with this in #bbpress as well.

Beau