Upgrading VBulletin 3.6.8PL2 to 3.6.9 errors

I'm trying to do the latest VBulletin upgrade..completely locked me out of any access to my forum. I'm thinking this has to do with some htaccess stuff I was working with here some time ago. I'm clueless on this stuff so any help would be appreciated. My forum is down so I'm desperate. Here's the error I get while attempting to run the upgrade script:

Warning: Cannot modify header information - headers already sent by (output started at /home/xxxx/public_html/forum/includes/config.php:1) in /home/xxxx/public_html/forum/install/upgrade.php on line 21

Warning: Cannot modify header information - headers already sent by (output started at /home/xxx/public_html/forum/includes/config.php:1) in /home/xxx/public_html/forum/install/upgrade.php on line 22

Warning: Cannot modify header information - headers already sent by (output started at /home/xxx/public_html/forum/includes/config.php:1) in /home/xxx/public_html/forum/includes/functions.php on line 2801

(Note, I xxx'd out my directory name)

Here is my htaccess file. Same with the xxx's

# Comment the following line (add '#' at the beginning)
# to disable mod_rewrite functions.
# Please note: you still need to disable the hack in
# the vBSEO control panel to stop url rewrites.
RewriteEngine On

# Some servers require the Rewritebase directive to be
# enabled (remove '#' at the beginning to activate)
# Please note: when enabled, you must include the path
# to your root vBulletin folder (i.e. RewriteBase /forums/)
#RewriteBase /

RewriteCond %{HTTP_HOST} !^www\.xxxx\.com
RewriteRule (.*) http://www.xxxx.com/forum/$1 [L,R=301]

RewriteRule ^((urllist|sitemap_).*.(xml|txt)(.gz)?)$ vbseo_sitemap/vbseo_getsitemap.php?sitemap=$1 [L]

RewriteCond %{QUERY_STRING} !vbseourl=
RewriteCond %{REQUEST_URI} !(admincp/|modcp/|chat|cron)
RewriteRule ^(.*.php(/.*)?)$ vbseo.php?vbseourl=$1 [L,QSA]

RewriteCond %{REQUEST_FILENAME} !.(jpg|gif)$
RewriteRule ^(archive/.*)$ vbseo.php?vbseourl=$1 [L,QSA]

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !^(admincp|modcp|clientscript|cpstyles|images)/
RewriteRule ^(.+)$ vbseo.php?vbseourl=$1 [L,QSA]

Could this be my problem? I can't even access my admincp.

I checked for the space on line 1 of my config.php, it didn't have it.

rename the .htaccess file to htaccess.txt so that it has no bearing. That will eliminate htaccess as the culprit.

That said, i don't think that's the case... sounds like a php error.

A plugin, perhaps?

Thanks Briansol,

I renamed the htaccess file, and I disabled vBSEO. Forum works fine now...so the problem is either in htaccess or vBSEO. I suspect htaccess. Any clues on how to proceed?