Sorry I don’t read French, but I can make out that you have acurrent version of avast! and you have a virus.
Try this link, it’s in French. It seems someone else has the same problem and recieved help there.
http://forum.telecharger.01net.com/telecharger/securite_virus_et_assimiles/virus/win32porndialer-bj_tool-406954/messages-1.html
btw this is an English forum