If you're using Firefox, check out the error console. I'm testing it now, albeit on the latest build, the pilot id, etc was giving issues. Now the doubling won't matter. But if you open the error console, clear it, then goto the ACARS map page, if there's anything, it'll show up.
But I was getting some Javascript errors with it not liking the remote URL, but I'm reading now that's due to the fact that it's on "localhost"