First posting an active link to a suspect site isn't wise, modify your post so it isn't active, e.g. fahrrad-handels.net
Second, it isn't detected by the Avast Antivirus signatures, so I don't understand why the Avast Ad on would be with the add-on (which I don't use).
I'm always a bit suspicious when a link to a site is posted when the antivirus doesn't detect it (suspect site spamming).