Grub install failed for /dev/sda

Install target is a new SSD with a 512MB /boot and 64GB / partition

Install GUI should give me options to resolve this error.

from /var/log/syslog:

May 13 21:44:07 ubuntu grub-installer: info: Installing grub on '/dev/sda'
May 13 21:44:07 ubuntu grub-installer: info: grub-install supports --no-floppy
May 13 21:44:07 ubuntu grub-installer: info: Running chroot /target grub-install --no-floppy --force "/dev/sda"
May 13 21:44:09 ubuntu grub-installer: /usr/sbin/grub-setup: Warnung: This GPT partition label has no BIOS Boot Partition; embedding won't be possible!.
May 13 21:44:09 ubuntu grub-installer: /usr/sbin/grub-setup: Warnung: Einbettung ist nicht möglich. GRUB kann in dieser Konfiguration nur mittels Blocklisten installiert werden. Blocklisten sind allerdings UNZUVERLÄSSIG und deren Verwendung wird daher nicht empfohlen..
May 13 21:44:14 ubuntu grub-installer: /usr/sbin/grub-setup: Fehler:
May 13 21:44:14 ubuntu grub-installer: »/grub/core.img« kann nicht korrekt gelesen werden.
May 13 21:44:14 ubuntu grub-installer: error: Running 'grub-install --no-floppy --force "/dev/sda"' failed.
May 13 21:44:46 ubuntu activate-dmraid: No Serial ATA RAID disks detected
May 13 21:44:46 ubuntu ubiquity[4439]: Reverting lockdown of the desktop environment.
May 13 21:44:47 ubuntu ubiquity: umount: /target: device is busy.
May 13 21:44:47 ubuntu ubiquity: (In some cases useful info about processes that use
May 13 21:44:47 ubuntu ubiquity: the device is found by lsof(8) or fuser(1))
May 13 21:44:47 ubuntu ubiquity[4439]: debconffilter_done: ubi-partman (current: ubi-partman)
May 13 21:44:55 ubuntu ubiquity[4439]: Reverting lockdown of the desktop environment.
May 13 21:44:55 ubuntu grub-installer: info: architecture: amd64/generic
May 13 21:44:55 ubuntu ubiquity: grub-probe: Fehler: cannot find a device for / (is /dev mounted?).
May 13 21:44:55 ubuntu ubiquity: grub-probe: Fehler: cannot find a device for /boot (is /dev mounted?).
May 13 21:44:55 ubuntu grub-installer: info: Identified partition label for /dev/sda2: gpt
May 13 21:44:57 ubuntu grub-installer: dpkg: warning: there's no installed package matching grub
May 13 21:44:57 ubuntu grub-installer: dpkg: warning: there's no installed package matching grub-legacy
May 13 21:44:57 ubuntu grub-installer: dpkg: warning: there's no installed package matching grub-efi
May 13 21:44:57 ubuntu grub-installer: dpkg: warning: there's no installed package matching grub-efi-amd64-bin
May 13 21:44:57 ubuntu grub-installer: dpkg: warning: there's no installed package matching grub-efi-amd64
May 13 21:44:57 ubuntu grub-installer: dpkg: warning: there's no installed package matching grub-efi-ia32-bin
May 13 21:44:57 ubuntu grub-installer: dpkg: warning: there's no installed package matching grub-efi-ia32
May 13 21:44:57 ubuntu grub-installer: info: Installing grub on '/dev/sda'
May 13 21:44:58 ubuntu grub-installer: info: grub-install supports --no-floppy
May 13 21:44:58 ubuntu grub-installer: info: Running chroot /target grub-install --no-floppy --force "/dev/sda"
May 13 21:44:58 ubuntu grub-installer: /usr/sbin/grub-probe: Fehler: cannot find a device for /boot/grub (is /dev mounted?).
May 13 21:44:58 ubuntu grub-installer: error: Running 'grub-install --no-floppy --force "/dev/sda"' failed.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: ubiquity 2.10.16
ProcVersionSignature: Ubuntu 3.2.0-23.36-generic 3.2.14
Uname: Linux 3.2.0-23-generic x86_64
ApportVersion: 2.0.1-0ubuntu5
Architecture: amd64
CasperVersion: 1.315
Date: Sun May 13 23:45:12 2012
InstallCmdLine: initrd=/casper/initrd.lz file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash -- BOOT_IMAGE=/casper/vmlinuz
LiveMediaBuild: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64+mac (20120425.1)
ProcEnviron:
 LANGUAGE=de_DE.UTF-8
 TERM=unknown
 PATH=(custom, no user)
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)