Help needed - Observe_form , passing parameters but ...

I think after 3 days I"m getting closer to getting my observe_form to work. At least now it’s rendering the partial , only with a nomethod (nil) error.
Here is the problem -> I don’t think I know how to grab the params correctly off the form.

Here is the form -

Category <%=

options_from_collection_for_select @categories, :id, :name %>

State <%=

options_from_collection_for_select @states, :id, :name %>

Terms <%=

options_from_collection_for_select @terms, :id, :name %>

Title City

<%= image_tag(“roller.gif”,
:align => ‘center’,
:border => 0,
:id => “roller”,
:style => “display: none;”) %>

<%= observe_form “asearch”,
:frequency => 0.5,
:update => ‘table’,
:before => “Element.show(‘roller’)”,

              :success => "Element.hide('roller')",
              :url => 'list',
              :with => "asearch" %>
<%= render :partial => "positions_list", :layout => false %>

From the server log , the parameters being sent -
Parameters: {“asearch”=>“position[state_id][]=35”, “action”=>“list”, “controller”=>“ajaxsearch”, “position”=>{“city”=>“Boston”, “title”=>"", “term_id”=>[“3”]}}

So the user can pick any number of choices in any number of elements

One thing that looks weird in the parameters above is -
“asearch”=>“position[state_id][]=35” as opposed to
“position”=>{“city”=>“Boston” and
“term_id”=>[“3”]}

anyway since the label names are position[field] in the controller I did a

@positions = Position.new(params[:position])

Yes as I said above getting a nil error on the finds.

Anyone ?

Stuart