Hello,

I have a LiteON 411S (FS0H firmware), and while trying to burn Verbatim DVD+R (MCC,4x media), I was pretty much getting this cryptic error every time I tried to burn:

Writing error. Cmdx, Scene, ASCx, ASCQ

and then "Invalid unit number". Well, guess what, I have 2 optical drives - one CDRW and one DVDRW. I disabled the CDRW in the hardware profile, and presto! Burnt fine!

Long story: I ran into the same problem (in an even more cryptic way, if that's possible ) while trying to upgrade the firmware on my drive from FSOB to FSOF. Firmware update went partway and then gave up, so I was pretty sure I screwed up my drive. Eventually, on some random whim, I disabled the other drive, and the update worked. The invalid unit number message got me thinking that perhaps the software was getting confused between the drives, and it appears to be true.

Anyways, if you get this invalid unit number error from Tmpgenc DVD Author, you most likely have two drives; disable the other drive and give it a shot.

Good luck,

-Chakra.