Hi, Thomas, and welcome to Apple Discussions. Are you using the Eject key to dismount the CF card from your desktop, or dragging the card's icon to the Trash (which also dismounts it)
before using the mechanical button beside the card slot to physically eject the adapter? If not, do. Ejecting the card (or adapter) physically before dismounting it might well cause a KP, and could result in lost data and/or a damaged card.
I'm interested to see that the Delkin card requires a downloadable driver for use with a Mac, and I wonder why. My two CardBus flash media adapters (one for CF and one for Smartmedia) require no third-party software at all, in Mac OS 8.6, 9.1. 9.2.2, Jaguar or Panther. Those aren't high-speed adapters like the Delkin, though; perhaps that's the difference.