Seems there has been a breakdown in communication between Imapsync developers and main distro developer teams – perhaps even perl – – who knows !!
Anyhow there is a problem at hand between Imapsync and Mail::Client.
Subroutine Authuser redefined at /usr/bin/imapsync line 2557.
imapsync needs perl lib Mail::IMAPClient release 2.2.9 exactly, future imapsync release may suppoort 3.0.x, but sorry not now. See file BUG_IMAPClient_3.xx
# Looks like your test died before it could output anything.
rpm --nodeps -e perl-Mail && rpm -ivh ftp://rpmfind.net/linux/dag/redhat/el5/en/i386/dag/RPMS/perl-Mail-IMAPClient-2.2.9-1.2.el5.rf.noarch.rpm