Re: Block size max cap should be raised to 2mb with block halving in July 2016 -Y/N?

So lets imagine a hypothetical scenario where I wanted to vote. I copy and paste one of the statements, and sign the message to get this:

Code:

-----BEGIN BITCOIN SIGNED MESSAGE-----
I believe that block size max cap should be raised to 2mb with block halving in July 2016
-----BEGIN BITCOIN SIGNATURE-----
Version: MultiBit HD (0.2.0)
Comment: https://multibit.org
Address:

-----END BITCOIN SIGNATURE-----

When I then paste that in the site, why would I get:

"Invalid signature! Please use bitcoin software to sign the message."