Try to flash the current Firmware from the Dangerous Brother's Firmware Page in pure DOS using MTKFLASH.
use the BIN file out of this archive to flash the drive in pure DOS (start diskette for example). Then flash the firmware with the following synthax:
mtkflash x w /m /b firmware.bin
Replace "x" with the drive's position:
Replace "w" with "r" to backup the current firmware.
I had a defective DVDRW 1004 here, the dealer said, that 50 out of 300 drives manufactured in Sept. 03 returned because of an hardware error built-in by BTC. The dealer replaced the drive with a later manufatured DVDRW1008 for free.