When adding a third party repository, make sure you add the correct release version as well as architecture to the Revisor YUM configuration file. Verify the location for the baseurl and/or mirrorlist you configure manually or through YUM. Make sure you expand any $releasever, $basearch and $arch variables.

There's a HOWTO on adding third party repositories included in this document at Section 6.1, “HOWTO: Add a Third Party Repository”.

See also Section 4.3.7, “Testing & Troubleshooting the YUM Configuration”