There most likely is a bogus email with the virus that also says something like that as well.
Title is ""Alert: Virus Scan Unavailable, Attachment Not Scanned" [test]" where [test] is the name of the original email with the attachment. Test contains "ATT00224.TXT (59 B)" which is a really small file.
Off of the [link|http://groups.yahoo.com/|http://groups.yahoo.com/] page for members is an important notice, clicking on this notice goes to this web site:
[link|http://groups.yahoo.com/local/service.html|http://groups.yahoo....ocal/service.html]
Based on an advisory posted by a leading anti-virus company, Groups will temporarily reject messages with the following subject lines:
* test
* hi
* hello
* Mail Delivery System
* Mail Transaction Failed
* Server Report
* Status
* Error
Notice it does not include "Alert: Virus Scan Unavailable...".