GRUB (grub2 i guess) won't install to the PBR
 

So here is the deal:

I installed osx mountain lion onto my pre-existing windows-ubuntu dual boot. Now I want to install chameleon to the MBR to replace GRUB. But before I do that, I need to make the linux partiton bootable so that chameleon will recognize. So in Ubuntu, I entered the following command

sudo grub-install /dev/sdb3 and got the following message:

/usr/sbin/grub-probe: error: cannot find a GRUB drive for /dev/sdb3. Check your device.map.

What does this even mean? Also note that sdb3 is the extended partition that has the ubuntu partition and the swap space. Please help.

Wrong partition. You can't install anything to an Extended partition as it is just a container for other logical partitions. You would have to point it to the correct partition which would be the / (root) partition where the Ubuntu filesystem containing boot files exists. If it is on an Extended partition, it would be sda5 or higher. You can get that info with the fdisk -l or df -h commands. The command you entered is wrong and the command below should work if your boot files are on sda5. The example below should be run from a Live CD of the same OS and with the same Grub version after creating the mount point (/mnt/sda5) and mounting the partition:

If the above fails, you can use the force option as in the example below:

You can get a lot of information on Ubuntu and Grub at the Ubuntu site at the link below:

https://help.ubuntu.com/community/Grub2/Installing

I fixed it, it wasn't the extended partition thing but a whole other mess. Thanks though!