Matias Keyboard No Longer Recognized by Leopard PB G4 But By Tiger

In February I took a month long trip with my Leopard-based PB G4 and Matias folding USB Keyboard. Everything worked together fine until after my return in early March when I noticed that the keyboard no longer worked with my laptop. Since my return I have received the normal Apple-push updates to my system. I tested the keyboard on my daughter's Dell laptop and it worked fine. I checked the keyboard with a friend's Leopard-based MacBook but to no avail. I called Apple Tech support and they initially informed me that it was not a Leopard issue because all third-party hardware should be automatically recognized by the computer. They also walked me through doing a reset of the computer to bring it back to original operating configuration. I contacted Matias who had their senior engineer look into the USB-capable keyboard and said they are not aware of any problems between the keyboard and Leopard. They also did not have a patch to push to me to get it connecting again but I will be keeping in contact with them about this. I brought my computer into an Apple store only to have them confirm that the keyboard is not being recognized by the USB drives, but there was nothing else they could do for me. I had the USB drives checked out a seperate computer store authorized to work on Apple computers and they both worked fine. At home, nothing that runs through the USB ports is NOT being recognized, everything works fine. While at the same computer store I found an older iMac using Tiger (10.4.7) and successfully tested it there after going through the normal syncing process. But on NONE of their Leopard-based Macs did it work which leads me to believe it is somehow related to either Leopard or an update everyone has received. While the folding keyboard may have only cost $99, I am hesitant to spend $75 for a service call at an authorized repair shop, and they advise me to re-consider having to visit them. Only because it is a great travel accessory for me to work on longer papers and projects rather than the laptop's own keyboard do I want to get this one working with my computer rather than buying another one. So my questions are, 1) how do I individually disable the updates received since March to determine which one is affecting recognition of the keyboard, and 2) why would the keyboard continue to work with Tiger and Dell but not on any Leopard-based Mac? Apple Tech's comments are primarily "it's not a Leopard issue, I should go somewhere else" to get it checked out.

The updates since March are:
Battery Update 1.4
Airport Client Update 2009-001
Airport Utility 5.4.1
Time Capsule and Airport Base Station Firmware Update 7.4.1
Front Row 2.1.7
iPhoto 8.0.2 Update
iLife Support 9.0.2
iWeb 3.0.1
iWork 09 9.0.1
iTunes 8.1.1 for Mac
iMovie 8.0.2
Server Admin Tools 10.5.6v1.1

Any assistance from the community would be greatly appreciated.

Rick