I'm having this on 2.0.31-9:
Sep 11 11:35:30 shalott kernel: EXT2-fs warning: mounting unchecked fs, running e2fsck is recommended
Sep 11 11:43:45 shalott kernel: EXT2-fs warning (device 03:41): ext2_free_blocks: bit already cleared for block 8472
Sep 11 11:43:46 shalott kernel: EXT2-fs warning (device 03:41): ext2_free_blocks: bit already cleared for block 9393
Sep 11 11:43:46 shalott kernel: EXT2-fs warning (device 03:41): ext2_free_blocks: bit already cleared for block 10758
Does it mean something I can understand?