grub install problem (wubi installation)

[yeradis]

grub install problem on a wubi installation

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: ubiquity 2.10.4
ProcVersionSignature: Ubuntu 3.2.0-20.33-generic-pae 3.2.12
Uname: Linux 3.2.0-20-generic-pae i686
ApportVersion: 1.95-0ubuntu1
Architecture: i386
CasperVersion: 1.312
Date: Fri Apr 6 00:54:32 2012
InstallCmdLine: BOOT_IMAGE=/ubuntu/install/boot/vmlinuz debian-installer/custom-installation=/ubuntu/install/custom-installation iso-scan/filename=/ubuntu/install/installation.iso automatic-ubiquity noprompt quiet splash boot=casper ro debian-installer/locale=en_US.UTF-8 keyboard-configuration/layoutcode=es keyboard-configuration/variantcode= -- rootflags=sync
LiveMediaBuild: Ubuntu 12.04 LTS "Precise Pangolin" - Beta i386 (20120328)
ProcEnviron:
 LANGUAGE=en_US.UTF-8
 TERM=linux
 PATH=(custom, no user)
 LANG=en_US.UTF-8
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)

[Ubuntu Foundations Team Bug Bot (crichton)]

Exception during installation:
Apr 5 22:54:29 ubuntu plugininstall.py: Traceback (most recent call last):
Apr 5 22:54:29 ubuntu plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 1720, in <module>
Apr 5 22:54:29 ubuntu plugininstall.py: install.run()
Apr 5 22:54:29 ubuntu plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 55, in wrapper
Apr 5 22:54:29 ubuntu plugininstall.py: func(self)
Apr 5 22:54:29 ubuntu plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 204, in run
Apr 5 22:54:29 ubuntu plugininstall.py: self.configure_bootloader()
Apr 5 22:54:29 ubuntu plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 998, in configure_bootloader
Apr 5 22:54:29 ubuntu plugininstall.py: "GrubInstaller failed with code %d" % ret)
Apr 5 22:54:29 ubuntu plugininstall.py: InstallStepError: GrubInstaller failed with code 1
Apr 5 22:54:29 ubuntu plugininstall.py: