i just installed a sony double layer dvd burner(model dru-710a). i have some files that i downloaded that read well from my hard drive thru nero show time. when i burn, it goes thru the process but the picture is scrambled(it asks me if i want pal or ntsc-i have chosen both and neither work). when i preview the project thru nero(just prior to burning), it is scrambled as well. what am i doing wrong???