Sorry, I just realized that where I said Thick, I wanted to say Thin.
I got it working by simply triying on a friend's computer with windows 7, now I have rockbox on my Ipod Classic, but the only problem I have is that when I plug it in my Macbook it says "The disk you inserted was not readable by this computer"
I got this a minute ago, now im investigating how to solve this. If anyone has an idea on what could it be I would appreciate some help

Thanks and sorry for the typo!