wheezy update-grub error

[Oleg <lego12239@yandex.ru>]

  Hello.

  I have the next error:

~# update-grub 
Searching for GRUB installation directory ... found: /boot/grub
Searching for default file ... Generating /boot/grub/default file and setting the default boot entry to 0
entry not specified.
Usage: grub-set-default [OPTION] entry
Set the default boot entry for GRUB.

  -h, --help              print this message and exit
  -v, --version           print the version information and exit
  --root-directory=DIR    Use the directory DIR instead of the root directory

ENTRY is a number or the special keyword `default\'.

Report bugs to <bug-grub@gnu.org>.

  Is this a bug? Or i do anything wrong?

  Thanks.