HELP! Lexar SD Card won't read in Mac!

[blando3]

I'm hoping someone can help me here. I just shot some footage for the first time with my AF100. The footage plays back in camera.
Using the Lexar 24-in-1 card reader, the card shows up in the Disk Utility but not on the desktop or in Finder. The Repair Disk option is grayed in, meaning I can't click on it, and I tried mounting the disk and it says it's unable to mount.

Any ideas? I have a shoot soon and need to figure out my workflow.
Thanks!

I've attached screengrabs of the disk utility and error message...

 

[blando3]

Oh, and the footage isn't important so I don't mind partitioning or erasing or whatever.

 

[blando3]

I think I got it. Looks like my cards are SDXC not SDHC. I need to upgrade my OS to 10.6.