Well, this 'answer' is entirely different. Fedora packages are
typically signed to prove that they come from approved Fedora sources.
yum check for that 'public key' to verify the package. Apparently, you
didn't get the package from an approved source, and so yum doesn't
want to install them -- basically it's trying to protect you.

If you are really sure that you want to do this:

yum --nogpgcheck localinstall

system-config-network-1.5.95-1.fc10.noarch.rpm
system-config-network-tui-1.5.95-1.fc10.noarch.rpm