Tony, Try letting Rails generate the route. I'm not sure exactly what you're doing, but the view should probably look a little more like this:
<% form_tag :action => 'create' do %> <%= hidden_field_tag "roster[id]", @roster.id %> <%= submit_tag 'Create' %> <% end %>
Make sure your controller has a corresponding 'create' action.
Dan Manges http://www.dcmanges.com/blog
