Can't inherit abstract function Creator

[Nerymon]

Hi :)
at first: my english isn't very good, sorry x.x
I hope you can understand my problem

I installed the mysidia script some minutes ago... I'm so happy that I found this script because I'm not good in php programming ^^"

I've finished the installion and wanted to open my site, but every time I get this message:

Fatal error: Can't inherit abstract function Creator::create() (previously declared abstract in UserCreator) in /var/www/vhosts/monfreaks.de/httpdocs/ado/classes/abstract/abstract_usercreator.php on line 3

I already checked the abstract_usercreator.php... but I have no idea what's the problem. Maybe anyone can help? :<

thanks in advance!