[Yum] Yum run at boot won't install a package group

[Jason L Tibbitts III]

When bringing up a new machine, I have a script that is called at the end
of rc.local which will do several "groupinstall"s to pull in package
groups depending on what the system is configured to do:

for i in math-base math-dev math-emacs math-browser math-multimedia math-office math-tex; do
 yum -y -d3 groupinstall $i | tee -a /tmp/updates
done

For some reason, math-base and math-dev won't install this way, but
the others will.  If I log in and run that command line myself,
everything's fine.  The output logged to /tmp/updates for the
math-base bit is:

Loading "installonlyn" plugin
Running "config" handler for "installonlyn" plugin
Yum Version: 2.6.1
COMMAND: yum -d3
Installroot: /
Ext Commands:
   math-base
Setting up Group Process
Setting up repositories
Baseurl(s) for repo: ['http://XXX/yum/fedora-core/5/i386/core']
Baseurl(s) for repo: ['http://XXX/yum/fedora-core/5/i386/livna']
Baseurl(s) for repo: ['http://XXX/yum/fedora-core/5/i386/updates']
Baseurl(s) for repo: ['http://XXX/yum/fedora-core/5/i386/groups']
Baseurl(s) for repo: ['http://XXX/yum/fedora-core/5/i386/local']
Baseurl(s) for repo: ['http://XXX/yum/fedora-core/5/i386/extras']
Getting group metadata
Reading Local RPMDB
Setting up repositories
Reading repository metadata in from local files
Setting up Package Sacks
Building updates object

and nothing else.  For a group that works, the log continues:

Resolving Dependencies
1152296102.65
--> Populating transaction set with selected packages. Please wait.

and so on, downloading headers and such.  If I log in and run that
command manually, the log continues like that as well, plus I get a
bunch of additional output like progress bars and such.

I'm completely at a loss as to why something would work from the
command line but not from a script at boot time.  I even tried putting
those groupinstall bits into a file, appending "ts run" and calling it
with yum -y -d3 shell, but the whole thing stops at:

Reading repository metadata in from local files
Setting up Package Sacks
Building updates object
Yum Version: 2.6.1
COMMAND: groupupdate math-base
Installroot: /
Ext Commands:
   math-base
Setting up Group Process
Getting group metadata

I don't see anything wrong with my yumgroups.xml file; xmllint seems
to parse it and doesn't complain about anything.  I put a copy of the
file at http://www.math.uh.edu/~tibbs/yumgroups.xml.

Thanks in advance for any hints.

 - J<