I'll repeat what others have said in other posts.
Reboot into single-user mode (command-s on boot), run
'fsck -y' (repeatedly if necessary) until no errors are reported.
Update prebindings:
'sudo update_prebinding -root /' and enter root password.
(If root login is not enabled there is a howto in (strangely enough
) the HowTo section.)
HTH!