GrubInstaller failed with code 1 (writing to SATA drive)

[Le jaune]

Binary package hint: ubiquity

I cannot install KUBUNTU on sda4 because GRUB cannot be install on sda0. I have a Mac with one disk and partitions (HFS+, HFS+, EXT3, EXT3).
I have iMac Intel Core Duo.
Log is :
Traceback (most recent call last):
  File "/usr/bin/ubiquity", line 166, in ?
    main()
  File "/usr/bin/ubiquity", line 161, in main
    install(sys.argv[1])
  File "/usr/bin/ubiquity", line 57, in install
    ret = wizard.run()
  File "/usr/lib/ubiquity/ubiquity/frontend/kde-ui.py", line 338, in run
    self.process_step()
  File "/usr/lib/ubiquity/ubiquity/frontend/kde-ui.py", line 828, in process_step
    self.progress_loop()
  File "/usr/lib/ubiquity/ubiquity/frontend/kde-ui.py", line 599, in progress_loop
    raise RuntimeError, ("Install failed with exit code %s\n%s" %
RuntimeError: Install failed with exit code 1
Traceback (most recent call last):
  File "/usr/share/ubiquity/install.py", line 1404, in ?
    install.run()
  File "/usr/share/ubiquity/install.py", line 385, in run
    self.configure_bootloader()
  File "/usr/share/ubiquity/install.py", line 1163, in configure_bootloader
    raise InstallStepError(
InstallStepError: GrubInstaller failed with code 1
Thanks.

[Le jaune (sebastien-jubeau)]

Wich news ?
Thanks.
Sébastien JUBEAU.