Email Greylisting

SL6.1 64bit on the greylist setting screen in virtualmin Greylisting is not available on this system : The Postgrey command postgrey was not found However, Virtualmin can attempt to automatically install the Postgrey greylisting package for you. Clicking the Install postgrey now button gives me:

Installing the Postgrey package ..

Installing package(s) with command yum -y install postgrey ..

Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package postgrey.noarch 0:1.32-3.el6 will be installed
--> Processing Dependency: perl(Net::Server) for package: postgrey-1.32-3.el6.noarch
--> Processing Dependency: perl(Net::Server::Multiplex) for package: postgrey-1.32-3.el6.noarch
--> Processing Dependency: perl(Net::Server::Daemonize) for package: postgrey-1.32-3.el6.noarch
--> Processing Dependency: perl(BerkeleyDB) for package: postgrey-1.32-3.el6.noarch
--> Finished Dependency Resolution
Error: Package: postgrey-1.32-3.el6.noarch (virtualmin)
           Requires: perl(Net::Server::Multiplex)
Error: Package: postgrey-1.32-3.el6.noarch (virtualmin)
           Requires: perl(Net::Server)
Error: Package: postgrey-1.32-3.el6.noarch (virtualmin)
           Requires: perl(BerkeleyDB)
Error: Package: postgrey-1.32-3.el6.noarch (virtualmin)
           Requires: perl(Net::Server::Daemonize)
 You could try using --skip-broken to work around the problem
 You could try running: rpm -Va --nofiles --nodigest

.. install failed!

.. installation failed!

and of course, it does. doing the same command line from ssh shell gives the same result.