/blockdata produces an unknown error

When I tried to use the exact /blockdata command that I successfully used in version 1.8, it reported an unexpected error.

What I expected to happen was...:
I expected it to change the block data like it used to.

What actually happened was...:
It just came back with an unexpected error.

Steps to Reproduce:
1. Just type in a /blockdata command in either the chat or in a command block.