Hello VastOne, many thanks for your quick reply.
Well, the exact error message I get is "error: file not found" followed by "grub recovery>_".
Output of fdisk -l is:
root@vsido:/home/vsido# fdisk -l
Disk /dev/sda: 320 GB, 320070320640 bytes
255 heads, 63 sectors/track, 38913 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 1 1959 15735636 27 (null)
Warning: Partition 1 does not end on cylinder boundary.
/dev/sda2 * 1959 1972 104422 7 HPFS/NTFS
Warning: Partition 2 does not end on cylinder boundary.
/dev/sda3 1972 13445 92156872 7 HPFS/NTFS
Warning: Partition 3 does not end on cylinder boundary.
/dev/sda4 13445 38914 204579742 5 Extended
Warning: Partition 4 does not end on cylinder boundary.
/dev/sda5 13445 37157 190466640 7 HPFS/NTFS
Warning: Partition 5 does not end on cylinder boundary.
/dev/sda6 37157 38750 12795772 83 Linux
Warning: Partition 6 does not end on cylinder boundary.
/dev/sda7 38751 38914 1309297 82 Linux swap
Warning: Partition 7 does not end on cylinder boundary.
Disk /dev/sdb: 8 GB, 8011422720 bytes
255 heads, 63 sectors/track, 974 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdb1 * 1 975 7831656 b FAT32
Warning: Partition 1 does not end on cylinder boundary.
root@vsido:/home/vsido#
There was already a grub installed on mbr by Crunchbang Waldorf. I chose sda and mbr during installation.
Following instructions on
http://manual.aptosid.com/en/sys-admin-grub2-en.htm#mbr-over-grub2 and after having mounted /dev/sda6 on /media/sda6 and run the "/usr/sbin/grub-install --recheck --no-floppy --root-directory=/media/sda6 /dev/sda" command I got the "/usr/sbin/grub-install: 352: .: Can't open /usr/lib/grub/i386-pc/modinfo.sh" message. I remembered then that this message appeared during installation of VSIDO too.
In a desperation I copied the modinfo.sh as well as the *mod, *lst and kernel.img files from /usr/lib/grub/x86_64-efi/ to /usr/lib/grub/i386-pc/ (guided by the error messages) and finally grub-install did run with no errors. After rebooting, I was presented again with the same error message.