Thanks Simon for your detailed answer.
I still think that Google doesn't give any credit to those links, because he knows that nobody is that stupid to buy those kind of links to his site. I think Google asks the same question as i do. Why would i buy/place crappy links pointing to my site? What is the logic in it.
I know that if i want to rank high i need lots of quality links, and for the moment it is possible to not rank higher because of those links. I'll see when i'll start to build some links, for the moment i have some big problems on site.
Thanks again.