I have installed using this Tutorial https://www.23systems.net/2009/07/installing-alterative-php-cache-apc-with-plesk-on-ubuntu/ and all is running fine. Even APC is caching everything and apc.php shows me all possible results.
But I am getting an error at /var/log/apache2/error.log
PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib/php5/20090626/apcu.so' - /usr/lib/php5/20090626/apcu.so: cannot open shared object file: No such file or directory in Unknown on line 0
On all possible php.ini files is the extension added like extension=apc.so and if I check the apc.so file inside the folder /usr/lib/php5/20090626/ than it is called apc.so and not apcu.so.
I greped all possible known files if I have somewhere mistyped the extension but I could find anything. Installed is the version of APC (3.1.13).