The Saitek drivers do not work on Macs. You have to use the plugins that are available. I use the older plugins by Tom Sedge and Sandy Barbour. I have Sparker's plugin as well, but on my system, the older plugins work just fine.
This sounds like a power problem. Even though you may have the panels plugged into a powered usb port or hub, you may need to get more power to them. Are you using a Saitek yoke? Are the panels plugged into the yoke or a powered usb hub? I have two radio panels, a switch panel and the multi panel. I have the "optional" power supply plugged into the yoke. I have the throttle quadrants and two panels plugged into the three usb ports on the yoke and the rest of my panels plugged into a powered port. Without the "optional" power supply for the yoke, the panels plugged into the yoke will not work. In my opinion, the power supply is NOT optional. You can order one here:
http://store.gameshark.com/viewItem.asp ... tegory=447
If you want the older Saitek plugins, let me know and I can send them to you, but I think your problem is power related.