[CentOS] elrepo problem?

So much for elrepo being a painless way to get working Nvidia drivers...

Yum update (or just update glibc) says:

--> Processing Dependency: /usr/sbin/ldconfig for package: nvidia-x11-drv-304xx-304.123-1.el7.elrepo.x86_64 --> Finished Dependency Resolution Error: Package: nvidia-x11-drv-304xx-304.123-1.el7.elrepo.x86_64 (@elrepo) Requires: /usr/sbin/ldconfig Removing: glibc-2.17-55.el7.x86_64 (@anaconda) Not found Updated By: glibc-2.17-55.el7_0.1.x86_64 (updates) Not found You could try using --skip-broken to work around the problem

What do those 'not found's mean?