Have you tried installing with
yum localinstall pkgname?
or
rpm -i pkgname, (after cd into pkg dir)
The add remove program gives a message that its unable to retrieve software information when it is not getting baseurl in the /etc/yum.repos.d/alltherepos.repo
Try uncommenting the baseurl line in
fedora-core.repo
fedora-updates.repo
fedora-extras.repo
and any other repo you may have installed.
if you are behind a proxy then add
proxy=http://a.b.c.d
ort to /etc/yum.conf