sarge ppc - boot error (fsck.ext3 does not describe a correct ext2..) yet partition mounts fine

["Rich Stanton" <stantonrj@cf.ac.uk>]

When booting debian sarge ppc on a powebook G3 (Lombard) I get the following
error:

fsck.ext3: No such file or direcotyr while trying to open /dev/sda1
The superblock could not be read or does not describe a correct ext2
filesystem.   If the device is valid and it really contains an ext2
filesystem (and not swap of ufs or something else), then the superblock 
is corrupt, and you might try running e2fsck with an alternate superblock:
    e2fsck b 8193 <device>

However if I then press Ctrl-D to continue the boot, /dev/sda1 is correctly
mounted as ext3 and is useable.

So, why does e2fsck give the error message, and how do I fix it?