I'm not sure how you used the command but, in Ubuntu you should do "sudo grub", prompted for and enter password, type "grub" get the grub prompt (grub>) and then enter the find command you have above.
You can use the geometry command from the grub prompt to get drive/partition information as seen by grub; example:
grub> geometry (hd0)
drive 0x80: C/H/S = 38792/16/63, The number of sectors = 39102336, /dev/hda
Partition num: 0, Filesystem type is fat, partition type 0xb
Partition num: 2, Filesystem type is ext2fs, partition type 0x83
Partition num: 3, Filesystem type is ext2fs, partition type 0x83
Partition num: 4, Filesystem type unknown, partition type 0x7
If you have multiple hard drives, run the geometry command and increase the number each time until you have listed all drives.