Stange behaviour with internet explorer

Hi!

I'm developing an application with Rails 1.2.6 and I've facing a weird
problem.

In a form, I'm using link_to_function that is aggregating a :partial,
the code is as follows:
  <table>
    <thead>
    <tr>
      <th>Marca</th>
      <th>Porcentaje</th>
      <th>Objetivo Mensual</th>
      <th>Destino</th>
    </tr>
    </thead>
    <tbody id="bonificaciones">
    <%= render :partial => 'bonificacion', :collection =>
@convenio.bonificaciones %>
    </tbody>
  </table>
  <%= link_to_function 'Agregar Bonificacion' do |page|
    page.insert_html :bottom, :bonificaciones, :partial
=>'bonificacion', :object => Bonificacion.new
  end %>

The :partial's code:
      <tr class="bonificacion">
      <% fields_for "convenio[bonificaciones_attributes]
[]",bonificacion do |bonificacion_form| %>
        <td><%=
bonificacion_form.collection_select :marca_id,@marcas, :alternate_id, :valor
%></td>
        <td><%= bonificacion_form.text_field :porcentaje %></td>
        <td><%= bonificacion_form.text_field :objetivo_mensual %></td>
        <td><%=
bonificacion_form.select :destino,Bonificacion::DESTINO %></td>
        <td><%= link_to_function
"Quitar","try{this.up('.bonificacion').remove()} catch(e) {alert('JS
error\\n'
+ e.name + '\\n' + e.message); throw e}" %></td>
        <td><%= link_to_function "this.up", "try{this.up(1)} catch(e)
{alert('JS error\\n' + e.name + '\\n' + e.message); throw e}" %></td>
      <% end %>
      </tr>

The 1st link_to_function is using this.up('.bonificacion').remove()
working w/o any problem with firefox and opera but not with internet
explorer.
Using try..catch and the alert found internet explorer doesn't
recognize 'this.up' as a valid method, AFAIK is a prototype
(Element.up) method but can not understand the reason for error. I
used the second link_to_function serve to pinpoint the error to
Element.up

Any help? recommendation? guidance?
If any additional information is required, pls ask me.

Thank you in advance.

Saludos,

Martín Trejo Chávez
http://chilli-coder.blogspot.com