In addition to the steps in the link above, I needed to change the Interface type to ASPI.
Go to Tools, Settings, I/O and under Interface select ASPI instead of the default SPTI.
Click "OK", and with a bit of luck it will detect your device. At least, it worked for me!
With that change, ImgBurn is working ok for me on Ubuntu 8.04.
FYI I got to looking at ImgBurn because of the bug in genisoimage causing ISO's created with it to be unreadable on Windows.
https://bugs.launchpad.net/ubuntu/+source/cdrkit/+bug/233942