http://www.fwb.com/ts/iMac_techalert.html
"FWB Software's Quality Assurance Team recently discovered a compatibility issue with the new iMac DV and DV+ and Hard Disk ToolKit. Until further notice, please refrain from using Hard Disk ToolKit in performing driver updates and initializing the drive.
Further testing confirms that the other new machines from Apple, the G4 MP and G4 Cube, are not affected by this compatibility issue."