DS18 - faulty firmware?

I have LTD-166S and upgraded from DS14 - DS18. The upgrade went on smoothly.

I have encounterd a few problems and noticed a few things :

  1. The opening of the tray is a little bit slow towards the end. No problems with closing.

  2. When I start Windows with a disc loaded in the drive, Windows would not start. Windows will detect the disc and then stop loading and no HDD activities.

  3. I try to burn on the fly and it failed in the middle of he process. The reading process will stop suddenly.

I think there is something wrong with DS18 because I have never encoutered these problems before. DMA is on, Nero Info Tool detects the drive.I can play DVDs and VCDs smoothly. Should I switch back to DS14 ?