scaffolding and date_select issues

I've started a fresh new app via SSH

here's what I typed:
$ rails test

cd test

$ ruby script/generate scaffold Evento nombre:string locacion:text

when I try to create a new 'evento' from the Eventos listing I get the
following error:

NoMethodError in Eventos#new

Showing eventos/new.html.erb where line #13 raised:

undefined method `fecha' for #<Evento id: nil, nombre: nil, locacion:

Extracted source (around line #13):

11: <p>
12: <b>Fecha</b><br />
13: <%= f.date_select :fecha %>
16: </p>

I've tried changing the line 13, like this:

<%= date_select( "fiesta", "fecha", :start_year => 2008 ) %>

but it doesn't work either. I can't see where's the error. can you
help me please?
I have rails 2.0, ruby 1.8.6 running in my server ( a
hosting account)