Hi, thank you for the help.
I've disable the widgets one by one to see if the problem was with those, and finally traced it back to the stats widget from
http://whos.amung.us/.
In fact I search it in Google and find out that there are a lot of people complaining about the same thing (
http://wordpress.org/support/topic/304563), wich is odd, since whos.amung.us its a very well known widget among bloggers, and the problem is reported only by some antivirus. Any way, trojan or not, I've change the widget to its non javascript version and everything its ok now, I didn´t want to scare off my readers

Thank you everyone, and sorry for the really bad english, i'm not use the write it
