Comment 8 for bug 392136

This affects me too.

$ apt-cache show grub-pc
Package: grub-pc
Priority: optional
Section: admin
Installed-Size: 1744
Maintainer: Ubuntu Core Developers <email address hidden>
Original-Maintainer: GRUB Maintainers <email address hidden>
Architecture: amd64
Source: grub2
Version: 1.97~beta4-1ubuntu4

Fails with:

### BEGIN /etc/grub.d/30_os-prober ###
Found Windows 7 (loader) on /dev/mapper/isw_cbibdfdhg_Volume01
menuentry "Windows 7 (loader) (on /dev/mapper/isw_cbibdfdhg_Volume01)" {
grub-probe: error: no mapping exists for `isw_cbibdfdhg_Volume01'
 chainloader +1
}
### END /etc/grub.d/30_os-prober ###

My hardware is a Intel P35 mainboard with ICH9 and a Windows 7 installation on a fakeraid.