If this hasn't been resolved, here's my twopenneth
You have 3 options to transfer data from a PC to a DVD I believe
A) You can use a DVD authoring program, like Pinnacle to burn the DVD. This gives you a movie, not a data file, it only creates a DVD-Video
B) You can 'burn' a DVD using a programme like Nero, this gives you a DVD with, in this case, a data file (such as a windows media file). This can only be done by using a DVD buring software programme
C) You can set up a re writable DVD to work just like a hard disk (so called drag and drop). Before you can do this however you need to set your system up, using a programme like InCD. I have used this succesfully with DVD-RAM format disks