I'm experiencing the issue with the dialog for setting the framerate for the animated tilesets like you mentioned, but when I test the game, the animated tiles work fine for me. I'm on a Win7 64-bit system, too. I tested the animated tiles in Flash and HTML5.
As for adding and removing frames, that works fine, too. It's just the framerate I'm having an issue with.
Did you try closing your game and then re-opening it before testing?