Fill barrier glitch

I was expecting to do command /fill in an area with barrier blocks and then fill an area inside of the blocks with air. I was standing in the area to be fill and activated the connected command blocks with the /fill commands in them. I was logged into my snapshot 14w05a server.

What happened was I got an error report saying there was an unexpected error.

Steps to Reproduce:
1. Put two command blocks connected by a redstone repeater and put a lever in the direction of the first command block in direction of the redstone repeater is facing.
2. In the first command block select an area to be filled with barrier blocks.
3. In the second command block select the area within the barrier blocks to be filled with air blocks.
4.Stand where the barrier and then air blocks are to be filled. Flip the switch to see an error report come up.
(I have attached the Minecraft Launcher Error Report.)