Hmm I just tried to verify it myself and get bad signature too... Not sure what I'm doing wrong?
That link has a bunch of HTML around the file. You need to 'download as text' using the link on that page (
http://paste.ubuntu.com/1503353/plain/) and that requires you to sign in to ubuntu's launchpad. If you do all that, the signature verifies just fine:
gpg: Signature made Sun 06 Jan 2013 06:32:45 AM PST using DSA key ID F1B69921
gpg: Good signature from "MP Stock Exchange (Visit http://polimedia.us/bitcoin/) "