Question : Attachment removed and body replaced with: "FILE QUARANTINED"

Hello everyone!
We have a customer trying to send us a critical datafile through email.  The problem is the email attachment is getting stripped from the email.  Email Client is Outlook XP.  We've also just upgraded to Exchange 2005 (which is why I am uncertain about this message below).

We are fairly certain the issue lies on the customer-side, because we receive these exact datafiles from customers nationwide all day - with no issue.

If possible, I would like to verify which firewall/email system/etc. adds this specific message below:
_________________________________________________________
FILE QUARANTINED
----------------

The original contents of Body of Message have been replaced
with this message because of its FragmentedMessage characteristics.
_________________________________________________________
I know "Body of Message" and "FrangmentedMessage" are variables.

Points to the first expert who can fill-me-in on which application adds this exact message.  

As always,
Thanks for your time and help!!
- Mike (OB)

Answer : Attachment removed and body replaced with: "FILE QUARANTINED"

Someone is using Antigen (probably the other party or you would know about it)

www.kbalertz.com/kb_924952.aspx