Be careful if you install MailScanner on your system.

If you have RPMFORGE repositories activated for YUM, MailScanner will break YUM due to some of the PERL dependencies.

You will cease being able to perform system updates, which is a bit of a problem.

The fix?

Disable RPM repositories, which will return YUM to its normal status.

nano /etc/yum.repos.d/rpmforge.repo

change enabled=1 to enabled=0

perform yum update and relax