If you have just updated your anti-virus program Avast and now it's detecting viruses and trojans like Win32:Delf-MZG in multiple programs -- probably you don't have to worry. This is happening to everybody who was pushed the new iAVS update for Avast.
The false positive error occurs since Win32:Delf-MZG uses the same script coding as most regular programs such as virus scanners.
In other words Avast is detecting viruses and trojans that are not really there. If you allow it to remove them or move them in the chest, it will make your applications stop working. This is the worst thing you can do because that means you will have to reinstall all of the "infected" programs afterward.
The solution is to wait for another avast! update or just disable Avast (right click on Avast in your system tray and stop it) and download another free anti-virus program until they get this straightened out.
Important update: a new update (version: 091203-1) that offers a fix has been pushed out. Currently Avast is not reporting any false positives. Manual update of iAVS is highly recommended.