Undefined index: tracking_requests_require_authentication

Hello,

I updated Piwik from 1.5 to 1.6 yesterday. There were no problems, no error messages and piwik is still working normally.
But since the update, I have hundreds of the following error messages in my /var/log/apache2/error.log:

[error] [client xxx.xxx.xxx.xxx] PHP Notice: Undefined index: tracking_requests_require_authentication in /home/user1/piwik/core/Tracker.php on line 403, referer: XXX Sex - Free Porn Movies - Porno Videos on XXX.com

Any idea what is happening?
I use the JavaScript-Tracking-Code that can be found here: XXX Sex - Free Porn Movies - Porno Videos on XXX.com
Piwik is running on a server with Debian 6.0 “Squeeze” and the included Apache/PHP/MySQL servers.

It llooks like the file config/global.ini.php was not uploaded/overwritten properly

Thanks! I manually copied the new global.ini.php into my piwik folder and the error is gone.