I think system setup doesn't matter, in fact I've istalled it on two different PC, even the 1640 are not really the same, because one was manufactured in april and the other in june (both from Malaysia and upgraded to BSLB).
Anyway I can use it only in the PC where I have a Pinnacle PCTV, else Qvideo is completely useless because if you don't have a TVcard and/or a SVHS input and/or a DV input buttons are greyed out (of course you only have 3 buttons, DV - TV - AV).