This sounds almost like a phishing scam, but on paper (instead of via e-mail).
What bothers me most is the statement that by signing, you authorize the cancellation of your current registration, but nothing stating this paper supercedes the previous registration. If you sign this, are you still registered to vote? Sure looks like you're not...
http://disruptthenarrative.com/2012/06/16/is-this-voter-fraud-in-the-making/

What is the point of rules that are not enforced?