[ubuntu] Upgrade from 12.04 to 12.10 server, Grub broken

Hi,
I upgrade two PC at home without any problem, however I got problems with the third.

http://paste.ubuntu.com/1448018/

As you can see, I used ubuntu-secured-remix to try to correct the problem ... with no success with the use of boot-repair

sdba : disk with ubuntu install and this is where is the problem
sdbb : disk with data / backup of my camera
sdbc : usb key.

How is it posssible to reinstall grub on this PC ?

Any help will be greatly appreciated !
Kind regards
Phil