Gentoo Windows7 双系统 Grub 设置问题

sda1 好像是 Window7 用于 boot 的？
C:                             sda2
D:                             sda3
extension                      sda4
/boot                  1 GB    sda5
/                      3 GB    sda6
/tmp                   10 GB   sda7
/var                   12 GB   sda8
/usr                   30 GB   sda9
/usr/portage           2 GB    sda10
/usr/portage/distfiles 4 GB    sda11
/swap                  5 GB    sda12
/home                  rest    sda13
/boot/grub/brub.conf
default 0
timeout 10
splashimage=(hd0,4)/boot/grub/splash.xpm.gz
title Gentoo Linux
root (hd0,4)
kernel /boot/kernel-genkernel-x86_64-2.6.32-gentoo-r2 root=/dev/ram0 init=/linuxrc ramdisk=8192 real_root=/dev/sda3
initrd /boot/initramfs-genkernel-amd64-2.6.30-gentoo-r5
title Windows 7
rootnoverify (hd0,0)
makeactive
chainloader +1
Grub 安装后只能进入 Windows，试图进入 Gentoo 会提示 Error 2: Bad file or directry type