Invalid node structure

my computer seems to be running fine but when i did a few monthly checks to make sure everything was running ok i found Invalid node structure after running disk utility
it will not let me repair it so i dont know what to do

i've tried /sbin /fsck - y but that couldn't repair it either

any ideas??

Sometimes booting off another disk such as your MAc OS X CD and run diskutil repair may have better results. Otherwise a backup, format, and restore is the only other solution.

thanks for the reply, can i also ask is it worth doing what you've said to restore when im not having any problems as of yet

(i've already backup everything )