I encountered something similar a while back, when I accidentally installed an el5 repo on a el6 machine.
To fix the problem, I:
- removed all el5 installed packages. (I found them with
rpm -qa | grep el5
) - removed el5 repo
- installed el6 repo
And after that all worked.
Seeing that "w5" tag in packages names, makes me think that you did a similar mistake and you installed a repository for centos 5 on a centos 6 machine.
Update: It looks like I was right. Webtatic it uses "w5" tag for el5 packages and "w6" tag for el6 packages. So you had an el5 repo installed on a el6 machine.