Perhaps you should use a distribution that includes all of the
packages you need rather than trying to bolt a bunch of
3rd party stuff on to CentOS.
I never, ever directly use 3rd party repositories. Neverhave had a problem. I even download mysql from mysql.com andbuild it from source, even go so far as rebuilding phpto link against the newer mysql(in CentOS 4's case). Noproblems.