with lastest grub2 and grml2usb the following happens

# grml2usb ~gebi/data/grml-medium_2009.05.iso
~gebi/data/grml64-medium_2009.05.iso /dev/sdb1
Executing grml2usb version 0.9.7
Using ISO /home/gebi/data/grml-medium_2009.05.iso
Identified grml flavour "grml-medium".
Copying files. This might take a while....
Note: grml flavour grml-medium is being installed as the default booting system.
Using ISO /home/gebi/data/grml64-medium_2009.05.iso
Identified grml flavour "grml64-medium".
Copying files. This might take a while....
cp: cannot create regular file
`/tmp/grml2usbcn6H-0/boot/addons/bsd4grml/LICENCE.TXT': File exists
Note: you can boot flavour grml64-medium using 'grml64-medium' on the commandline.
Installing default MBR
grub-setup: warn: Attempting to install GRUB to a partition instead of the MBR.
 This is a BAD idea.
grub-setup: warn: Embedding is not possible.  GRUB can only be installed in this
setup by using blocklists.  However, blocklists are UNRELIABLE and its use is
discouraged.
grub-setup: error: Cannot read `/grub/core.img' correctly
Traceback (most recent call last):
  File "/usr/sbin/grml2usb", line 1736, in <module>
    main()
  File "/usr/sbin/grml2usb", line 1728, in main
    handle_bootloader(device)
  File "/usr/sbin/grml2usb", line 1673, in handle_bootloader
    install_bootloader(device)
  File "/usr/sbin/grml2usb", line 679, in install_bootloader
    install_grub(device)
  File "/usr/sbin/grml2usb", line 632, in install_grub
    logging.critical("Fatal: error executing grub-install (please check the
grml2usb FAQ)" % error)
UnboundLocalError: local variable 'error' referenced before assignment
grml2usb ~gebi/data/grml-medium_2009.05.iso  /dev/sdb1  0,74s user 4,59s system
9% cpu 55,012 total