I had an old matsushita 6x drive that needed different drivers then those loaded on the diskette, Perhaps if you check for them.
Another thing to check, make sure the CDRW is set to primary master, the CDrom is set to secondary slave.
Then try removing the CDrom (leaving only the CDRW as secondary master) and try booting using a bootdisk from
www.bootdisk.com (or try yours that you have)
Personally I wouldn't bother putting a 2x CDrom in that system. (that matsushita one is.)
Come to think of it, I think Urban Squirrel is right that drive, which I had one of, uses a panasonic interface, same number of pins, but had to attach to a soundcard, I knew that model number sounded familiar.
That's why it keeps mentioning SBCD.sys everywhere I look, Don't hook it up at all, just the burner, if the burner still doesn't work, try another boot disk (I mentioned the site above) if it still doesn't work, try setting it to primary slave,