In latest mratwork.repo, Kloxo-MR using MariaDB 10.0 instead 5.5. And you are using MariaDB 5.5.
I don't know what's happen in latest version of MariaDB 5.5 because Kloxo-MR recommend to use 10.0.
So, modified your /etc/yum.repos.d/mratwork.repo:
# for mariadb
[mratwork-mariadb-32]
name=Kloxo-MR - mariadb 32bit repo
baseurl=http://yum.mariadb.org/10.0/centos6-x86
enabled=0
gpgcheck=0
to:
# for mariadb
[mratwork-mariadb-32]
name=Kloxo-MR - mariadb 32bit repo
baseurl=http://yum.mariadb.org/10.0/centos6-x86
enabled=1
gpgcheck=0
and then running 'yum clean all; yum update'.