I don't think so. I'm far from an expert on this stuff, but I can transfer files both ways between my 770 (2006 OS) and PC using the BT file transfer service. DUN (Dial Up Network) is associated with internet access, right? My PC doesn't use that.

BTW, in 2007HE I couldn't figure out how to access my PC from the 770. In File Manager it doesn't list the 'phone' device selected, unlike the 2006 OS. And in 2007HE in Control Panel it wouldn't let me select the PC BT as the 'phone', again unlike 2006 OS. Yes, the PC BT name shows up in the Control Panel->Bluetooth along with my celll phone, but how to make the PC show up in the File Manager?