A fix has been found for the "dead key" problem with Apple’s Pro Keyboard and older Macs.
Downloading the Apple UBS DDK drivers (1.4.6b2) should remedy the problem.
However, the Apple drivers are beta and are targeted at developers. The advice is to use them with caution. They're online and have the following note to anyone considering using them: "The enclosed software is for developmental purposes only. This release of software will support all iMacs, iBooks, Power Macs and PowerBooks with built-in USB. It will also support USB PCI and Cardbus cards from other vendors. Carefully read the installation instructions detailed in the DDK Readme file. "
Macworld reported on September 6, that four keys on Apple's Pro keyboard didn’t work with Macs shipped prior to July 19.