Interaction between controllers - ruby-on-rails-3

Question

On my web app I have a login page which is in the Pages Controller called welcome.html.erb
Inside it has a simple form for login and a simple for for sign up, both on the same page.
If the user signs up with wrong credentials (like password confirmation wrong, or length of password and etc) the controller that handles this is the new method in the Users Controller.
Inside the new method it checks if a user is created, and if not I'd like it to return to the welcome method in Pages Controller, passing to it the errors that were created during the user's creation.
It seems that if I do a
redirect_to root_path
The error count of the signup is reset when returning to the root page. If instead I call some other action of the users controller I do see the errors.
But since all of the html code is in the welcome view I don't want to replicate the code in the users controller views as well..
Is there a way to pass that errors data to the pages controller?
The partial for the error is
<% if object.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(object.errors.count, "error") %> prohibited this <%= object.class.to_s.underscore.humanize.downcase %> from being saved:</h2>
<p>There were problems with the following fields:</p>
<ul>
<% object.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
Which I call using
<%= render 'shared/error_messages', :object => f.object %>

Answer 1

redirect_to welcome_path
(Or whatever the actual path is.)

Answer 2

From the Users controller I called
flash[:errors]=#user.errors
and then I changed the partial to be
<% if object.any? %>
<div id="error_explanation">
<h2><%= pluralize(object.count, "error") %> prohibited this <%= object.class.to_s.underscore.humanize.downcase %> from being saved:</h2>
<p>There were problems with the following fields:</p>
<ul>
<% object.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
Which I called using
<%= render 'shared/error_messages', :object =>#user_errors %>
That solved the issue for now..