too many inodes error from fsck

[Stephen Borrill <netbsd%precedence.co.uk@localhost>]

1# fsck -fy /dev/rdk0
** /dev/rdk0
** File system is already clean
** Last Mounted on /data
** Phase 1 - Check Blocks and Sizes
1288780186 DUP I=317676426
INCORRECT BLOCK COUNT I=317676426 (8 should be 48)
CORRECT? yes

1288780182 DUP I=317676427
1288780183 DUP I=317676428
1288780184 DUP I=317676429
1288780185 DUP I=317676430
1578985280 BAD I=366356386
too many inodes 1373937901
2#

This is on NetBSD 5.2_STABLE from Wed May  1 10:13:58 BST 2013.

Is NetBSD 6 likely to be any better at fixing this?

--
Stephen