[rexford.kim]

When I try to use the MediaWiki/vBulletin Single Sign-On and try to edit the MediaWiki pages I get this error from MediaWiki and I get Apache errors for PHP. If I do not use the Single Sign-On edits to the MediaWiki page go through fine.

Sorry! We could not process your edit due to a loss of session data. Please try again. If it still doesn't work, try logging out and logging back in.

I CANNOT edit the mediawiki or save preferences with the Single Sign-On installed. I did the /includes/User.php edit but I still cannot EDIT!

Open wiki/includes/User.php FIND:
PHP Code:
define( 'EDIT_TOKEN_SUFFIX', '+\\' );
Replace with:
PHP Code:
define( 'EDIT_TOKEN_SUFFIX', '+#+' );

Posted Solution on MediaWiki that does not work for me.
Assuming you get this error even when you do have a seemingly valid logon session:

Check if /var/lib/php5 is writable and not readable for user and world ( # chmod 733 /var/lib/php5 )
Check to see if your session.save_path value in php.ini is valid and writable to the webserver - PHP configuration.
Check to see if there is enough disk space.

After making changes restart Apache:

/etc/init.d/httpd restart

I get Apache errors for PHP:

[Wed Aug 19 17:47:02 2009] [error] [client 10.15.15.41] PHP Notice: Use of undefined constant VB_SYSTEM_PATH - assumed 'VB_SYSTEM_PATH' in /var/www/html/wiki/LocalSettings.php on line 28, referer: http://www.website.com/wiki/index.ph...&action=submit

[Wed Aug 19 17:47:02 2009] [error] [client 10.15.15.41] PHP Notice: Constant CWD already defined in /var/www/html/forum/global.php on line 16, referer: http://www.website.com/wiki/index.ph...&action=submit

[Wed Aug 19 17:47:02 2009] [error] [client 10.15.15.41] PHP Notice: Use of undefined constant VB_SYSTEM_PATH - assumed 'VB_SYSTEM_PATH' in /var/www/html/wiki/LocalSettings.php on line 28, referer: http://www.website.com/wiki/index.ph...&action=submit

[Wed Aug 19 17:47:02 2009] [error] [client 10.15.15.41] PHP Notice: Constant CWD already defined in /var/www/html/forum/global.php on line 16, referer: http://www.website.com/wiki/index.ph...&action=submit