Do not install Virex 7.5 or download Engine updates via Versiontracker.com or such as this would effectively break cgvirusscan.
In Virex 7.5 the --mime command line option of vscanx (or uvscan) has been removed (for whatever reason). This option is needed to unpack mime encoded messages and attachments. Without --mime basicaly all virus infected mails will slip through unitentified.

Click on the image and have a good laugh!

Image from John R Chang