chroot setup problem

[Haines Brown]

I attempt to chroot from /dev/sdb on /dev/sda. 

  # mount /dev/sda1 /mnt/debinst

I verify it is mounted and then do:

  # LANG=C.UTF8 /usr/sbin/chroot /mnt/debinst /bin/bash
  /usr/sbin/chroot: failed to run command `/bin/bash': No such file or  
    directory 

/usr/bin/chroot exists. So does /mnt/debinst. So does /bin/bash.

Haines Brown