The current 2010-02-03 VPS signature flagged the current ClamAV main.ndb (signature file) as containing a trojan.
NOTE: ClamAV (http://www.clamav.net/) is not an on-access scanner, but an on-demand file scanner. So the Avast alert was only while manually scanning a file with ClamAV.
quote:
Even when one of them is disabled for use as a stand-alone scanner, it can affect the other. Anti-virus software components insert themselves into the operating systems core and using more than one can cause instability, crash your computer, slow performance and waste system resources.
Two Antivirus
http://www.bleepingcomputer.com/forums/index.php?s=0187bd134b8802571f702651c340acdc&showtopic=260844&view=findpost&p=1441638