Error after update

[jaro61]

After update PS on version beta 3 this error is showing.

Warning: require_once(C:\xampp\htdocs\shop\config/../classes/Poll.php) [function.require-once]: failed to open stream: No such file or directory in C:\xampp\htdocs\shop\config\config.inc.php on line 20

Fatal error: require_once() [function.require]: Failed opening required 'C:\xampp\htdocs\shop\config/../classes/Poll.php' (include_path='.;C:\xampp\php\pear\') in C:\xampp\htdocs\shop\config\config.inc.php on line 20

What is wrong?

Thanks