Cannot unmount SDCard

[rickpref]

I'm on Ubuntu 9.10 on a eeepc 1000H. I have a 4gb SD Card in the SD slot that has Puppy Linux installed on it. I'm trying to reformat the card in GParted but I keep getting this error whenever I try to unmount.

Error <i>org.freedesktop.Hal.Device.Volume.UnknownFailure</i>

Thanks...