I have been trying to create a ~16 gb partition on my macbook pro for the last few days. I have 44 gb free space on my computer.

I keep getting this error: "Could not modify partition map because filesystem verification failed"

I have repaired the permissions on my disk multiple time and I even bought iDefrag and defragged my computer per the suggestion of people online.

But i am still getting the same error. What should i do?