Strange Warnings on updating tonight

[Les Howell]

Hi, everyone,

	I am running F19 on an AMD 64 bit system.  I was notified of updates
and chose to install them, but something went wrong.  Didn't see the
error message, but it stopped.  And prompted me to reboot, which I did.
They tried yum clean-all followed by yum update.  
	Here is what I got back:

Warning: group core does not exist.
Warning: group gnome-desktop does not exist.
Warning: group multimedia does not exist.
Warning: group firefox does not exist.
Warning: group guest-desktop-agents does not exist.
Warning: group base-x does not exist.
Warning: group anaconda-tools does not exist.
Warning: group electronic-lab does not exist.
Warning: group fonts does not exist.
Warning: group milkymist does not exist.
Warning: group hardware-support does not exist.
Warning: group dial-up does not exist.
Warning: group printing does not exist.
Warning: group libreoffice does not exist.
Warning: group input-methods does not exist.
Warning: group standard does not exist.
No packages marked for update

I am guessing that these are groups that are supposed to be in the
groups of "users and groups".  

	Do I need to create these and if so, why?  I haven't had to do this
before.