Guys, were those detections caused by an on-demand (i.e. manual) scan, or rather by a shield?
If it was a shield, could someone please open the file
c:\Documents and Settings\All Users\Application Data\AVAST Software\Avast\report\FileSystemShield.txt
search for the relevant entry about tcpip.sys (should be somewhere at the bottom), and paste here the few lines (the detection, plus the subsequent action(s) on the next line)?
Thanks.