External BenQ 1620 Not Writing

I recently purchased a BenQ DW1620 drive to use externally. Upon failed attempts in the beginning, I saw the post about upgrading the firmware. I did that, and still nothing. I reinstalled all burning software (Nero, Alcohol, imgBurn, Roxio, etc) and reinstalled the USB drivers for the USB 2.0 on the laptop.

Windows recognizes the drive as a dvd-rw drive, can read all media without a problem, but no writing.

Wasted about 10 Sony DVD+R discs and 5 HP DVD-R discs, and still have only coasters.

Dell Inspiron 6000 Laptop
1GB DDR2 PC4000
Internal CD-RW/DVD-ROM drive
Intel WiFi & NiC
ATI Radeon Mobility x300

Any ideas guys?

What type of usb-ide adapter do you have? I tried the firmware for the external 1625 but saw no improvement so I went back to B7V9. I can only burn at 4x with this particular adapter ( R-Data/NGear).

Strongly suggest that it could be a problem with the external enclosure. The only one I have had success with is one using a Prolific 3507 chipset, all the others I have cause write errors.