I've found this error in my logs:
relocation error: /usr/lib64/libmyodbc5.so: symbol strmov, version libmysqlclient_16 not defined in file libmysqlclient_r.so.16 with link time reference
yum install mysqlclient16 ... 184 packages excluded due to repository priority protections Setting up Install Process Package mysqlclient16 is obsoleted by mysql-libs, trying to install mysql-libs-5.1.59-1.el6.art.x86_64 instead Package matching mysql-libs-5.1.59-1.el6.art.x86_64 already installed. Checking for update. Nothing to do
i've used the atomicrepo using the latest mysql-version (mysql-5.1.59-1.el6.art.x86_64) on a server driven by CentOS6.
Plesk: This also appears in Plesk 10.3 > Application Vault as "Error 500"
edit: i've posted my solution as a response, maybe somebody will need it