He had changed from zen mini to lxde, maybe he means install latest lxde iso, and there is the sources.list outdated.
A simple, moment step in my labor....
su -c 'rpm -Uvh http://distro.ibiblio.org/pclinuxos/pclinuxos/apt/pclinuxos/2010/SRPMS.updates/apt-sources-list-1.0.5-1pclos2013.src.rpm'
should solved the problem.
Regards
Daniel
ps. edit the Subject line...