Troubles Modifying navbits in MyBB

I'm trying to remove the "index.php" part form the breadcrumbs to avoid double content penalties from search engines on my MyBB forum, but keep having troubles with it.

What I found out is that this part of global.php controls the breadcrumbs:

// Add our main parts to the navigation
$navbits = array();
$navbits[0]['name'] = $mybb->settings['bbname_orig'];
$navbits[0]['url'] = $mybb->settings['bburl']."/index.php";

Code (markup):

It seemed pretty straightforward so I removed the "index.php" part from the code leaving it at:

// Add our main parts to the navigation
$navbits = array();
$navbits[0]['name'] = $mybb->settings['bbname_orig'];
$navbits[0]['url'] = $mybb->settings['bburl']."/";

Code (markup):

But then I keep getting a major error on top of my forum which reads something like this:

Warning [2] Cannot modify header information - headers already sent by (output started at /www/DOMAINNAME.com/public_html/global.php:1) - Line: 1548 - File: inc/functions.php PHP 5.2.9-pl2-gentoo (Linux)
File Line Function 
[PHP]   errorHandler->error 
/inc/functions.php 1548 header 
/inc/class_session.php 365 my_setcookie 
/inc/class_session.php 98 session->load_guest 
/global.php 56 session->init 
/index.php 18 require_once 

Code (markup):

Does anyone know how to make it work? How do I truncate the homepage URL in breadcrumbs so it links to the URL with a trailing slash but without the index.php appendix to it?

Help

 

Which version of MyBB are you using? I just tried this with the latest version, 1.4.10, and I'm not seeing any errors.

Do you have any plugins or modifications installed?

 

It's the latest version (v1.4.10). I have a SEO plug in, undo delete and multi video embed. Otherwise it's a clean install on a brand new domain with no modifications whatsoever. You should try to refresh your forum to make sure it's not pulling it from the cache. It definitely does break it as I have tried it on three independent installations.

 

I've refreshed a few times and I checked the navigation to make sure it changed, and it did. I'm seeing no errors. This is a brand new install with no changes or plugins.

Is the error on the index? When viewing a thread or what?

 

Dude, that's weird. I've tried it again and sure enough it breaks each of my two existing and one new bord. WHat the hell is happening on my end?