What machine do we have t his thing on, and on what system?
Your probably know USB booting is limited only to OS 9.0.4. If what came with it doesn't work try one of the third party CD drivers. FWB is not known for jumping into things fast. Hard Disk ToolKit is just now guaranteed to work right with OS 9, almost a year later, (yes, I know they claimed there were no major problems with 3.0, but they didn't claim compatibility until 4.0)
There are a couple of other CD drivers out there, you'll just have to search for them and check for boot capability.