Error quarantining the object - - contained infected files

Every times Nod found a virus in OE, can't save a copy of it in Quarantine.
It's not a problem because it delete the file but it's possible that it will find a false positive and delete it and no copy of the mail will be saved.
Example of log:
Time Module Object Name Threat Action User Information
03/02/2007 10:25:04 IMON email message from: Mack F. Toby <xxxxx@xxxxxxxx> to: XXXXX@XXXXXXXXXXX with subject Feeling Horny? dated Sat, 3 Feb 2007 13:29:16 +0530 downloaded from server xxx.xxx.xx.xx:110 Win32/Nuwar.gen worm Error quarantining the object - - contained infected files XXXXXXXXX\(User name)