Mac mini sd card works with server but not OSX

I have a new Mac mini that came with server 10.6 preinstalled. I installed OSX 10.6.3 with a retail disk, and SD cards stopped being recognized. I installed all software updates but still no SD card reader.
I reinstalled OSX server, and the SD card came back. Is there a driver that needs to be installed that is not in the OSX retail disk?

Did you run software update after loading 10.6.3?

Yes, I did run all software updates.*
I noticed however that the server os has a .kext file in the extensions folder that is missing in the osx extensions folder. I'm not at my computer now, but it was named something like "appleSD..."
I looked for documentation on how to install a .kext manually but all I found where articles related to osx86.*

I can't help you there because my machine does not have that extension since it does not have a SD card reader.

However, are you sure the version of Snow Leopard that you used to install on the Mini is in fact for the Mini? Or a retail copy of Snow Leopard?

It's the retail disk. I assumed it would include all drivers for current apple machines.

If it's a retail disk it should include all the drivers. Although I'm not sure about the upgrade disk. You might want to give Apple support a call and ask about that though.