You could report the fake account with what you've stated, perhaps getting it an IP Ban. From what I've read, MySpace doesn't IP ban very often, and usually only from the same IP creating a new account, but in your case this would be what you are looking for - the account banned and the inability to create another from the same IP address.
However if they were using proxies or another computer with a different IP address, they can still get around it. There really isn't a way to completely stop this problem if the harasser was determined to continue.
The only place success comes before work is in the dictionary.