I'm guess you got access to PI Webparts 3.0 through our Techsupport team. Because PI Webparts 3.0 is still on limited release, we have not posted the install kits on the vCampus Download Center at the moment. If you got in touch with our Techsupport team and arranged for the downloads with them, I would suggest that you contact them again for access to PI SQL for AF Server install kit as well.
Because the TreeView Webpart in PI Webparts 3.0 gets the information from AF via PI SQL for AF Server, it is a necessary component and you should have access to it together with PI Webparts 3.0.
As Han pointed out this look like the PI WB 3 version. The afsqlservice you referred to is part of the PI OLE DB Enterprise provider; don't confuse this with the PI OLE DB provider. The enterprise version provides access to AF. As a note this OLE DB provider is currently only available as a pre-release version on vCampus (i.e. not for production) and does not work with the 2010 versions of PI & AF, as far as I'm aware. The final versions will be release in 2010 Q2 according to the engineering plan.