I get KPs using my Compact Flash PCMCIA adapter, too. And a friend of mine with a Memory Stick PCMCIA adapter has the same thing. (Same with 10.2.4, .5, .6.)
The SanDisk ImageMate 6-in-1 that I use on my desktop (the reader is USB 2.0 capable, but my Mac is USB 1.1) sometimes gets weirded out, too... I guess OS X's flash media access is generally just... bad!
tooki