After install some programs are missing

I just did an install and during the install it would occasionally hang
while downloading (there were messages on the firewall about arp being
reassigned).  It made it through the installation but there are several
programs missing (passwd, mount, umount) so it drops me to a root prompt
during boot.  I am guessing that not everything downloaded correctly due
to the network troubles?  Is there a way to do another emerge and get
these missing programs installed?

Thanks
  -Scott