First step is to check whether you actually have multiple versions of the same package installed, or just that RPM/Yum think so, ie. does the command:

   rpm -q glibc

report one or more packages?

If the former, the you can probably fix the problem by a clean and reset of both the RPM and Yum package data (which is harmless in any event):

   # Remove the RPM package DB:
   rm -f /var/lib/rpm/__db.*
   # Rebuild the RPM package DB:
   rpmdb --rebuilddb
   # Clear the Yum cache:
   yum clean all
   # Rebuild the Yum package data (and check for updates):
   yum check-update

If the latter, then try the following:

   # Install yum-utils (if you don't have it already):
   yum install yum-utils
   # Clean up duplicate packages
   # NOTE: I'd recommend a review of the Man page and use of the information options first:
   package-cleanup --cleandupes


HTH,

--
Andy

The only person to have all his work done by Friday was Robinson Crusoe