Just for the hell of it, I put my sandisk SD card adapter that holds my 2gb mini sd card in the reader. It mounted, I was able to read and write to it as if were completely normal. I use this card in my little Canon SD30 digital camera.
Specs of the computer is no different than than most here. 2gb of ram from Crucial, OSX installed with the Type11 method, and all updates are current. I did not have any other cards to try but I put it in and took it out several times and it works flawlessly.
I thought it wasn't supposed to work...?