JS:ScriptIP-inf [Trj] on a legit site?

avast forum http://forum.avast.com/index.php?topic=65494.0

I have problem with JS: ScriptIP-inf [Trj] on my many sites. Most of them I ziped and left for some better times.

I am interested is there any way I could solve this, I mean is there a way I can clean all of this sites?