Ok, first need to get updated info on your system, so as to get ubuntu grub configured without breaking something.
Originally Posted by desertskymc
Mostly info about drives and partitions, but first about grub on the Ubuntu istallation at sdc4, not grub-efi on the OSX partition.
Remove all CD's and usb sticks.
Restart into rEFIt screen and run the Partiton Tool, and let it Update the MBR if needed.
Restart again into ubuntu on sdc4. (I hope you can post direct from ubuntu)
In a terminal run these commands and post the lot.
Then restart into Mac OSX, and in a terminal
$ sudo dpkg -l grub grub-pc
$ uname -a
$ lsb_releasee -a
$ sudo parted /dev/sda p free
Should list all 3 drives and partitons.
How to do the actual ubuntu grub reinstall will depend on which grub version found in ubuntu.
Oh, and you need to make a rEFIt CD - download the Mac disk image from refit web site and burn in Mac OSX.