Edgar,
It's as I thought. If you look at your pkg folder you will see that when you installed Beta 3 with Espanol there were compiler errors when it tried to create the web precompiles (the installer didn't complain about this - we'll look into making that better) and then any web application will throw errors when compiling (such as Plato). If you copy these two attached files into Pkg and precompile the system packages and then Plato you'll be fine.