First, I hate facebook.

That said, the old method using the FBML static app ( http://www.facebook.com/apps/application.php?id=4949752878&b ) does not work anymore.
The limit is that you can add only one box since there’s no more the link “Add another FBML box” (see old method here http://youtu.be/sWNMn9FE6fc ).

So the question is “how can I add several boxes to my facebook page”?
Answer: “add several FBML boxes to your page using another app”

This is the new application:
http://www.facebook.com/apps/application.php?id=176392299079602&sk=reviews
Some other info:
http://apps.facebook.com/tabfbmledit/?ref=ts

Wait, there’s more …
At the f8 Developer Conference in Sept 2011, Facebook announced that on June 1, 2012 FBML will be completely disabled. (is this true?)
Anyway, here’s an application that should replace the Static FBML:
http://www.facebook.com/apps/application.php?id=176217385757369
Right now this application allows you to add only one box, so I would suggest you to use the “Tab FBML” app.