Roberto, you are a professional and a gentleperson. Thank you and your team for giving this the attention and effort you have. Even if it turns out to be an infection, I'm still happy to have hard working people like you guys in our corner.
As a note I forgot to include in the email, or here: That oUltraf.sys file was located in C:\Documents and Settings\{My username}\Local Settings\Temp\ , which seems somewhat suspicious in it's own right.