RJS error when using replace_html

I have the following code in the controller. I am populating a drop
down box dynamically based on the selection from another drop down
box.

def update_releases project = Project.find(params[:project_id])
releases = project.releases puts "releases==#{releases}"
render :update do |page| page.replace_html 'releases', :partial =>
'releases', :object => releases end view code:

-form_tag reports_path(report_type=1),:method => :get, :multipart =>
true ,:id => "filter" do %table.grid.full %tr
%td.grid.full_panels{:style => "width: 20%"} Project:
%td.grid.full_panels{:style => "width: 20%"} //= select_tag
"projects",options_from_collection_for_select(projects,"id","name",params[:projects]),
{:onchange => "#{remote_function(:url => {:action =>
"update_releases"},:with => "'project_id='+value")}"} =
select_tag
"projects",options_from_collection_for_select(projects,"id","name",params[:projects]), :class
=> "update_releases" %td.grid.full_panels{:style => "width:
20%"} Releases: %td.grid.full_panels{:style => "width: 20%"}
<div id="releases"> = render :partial => 'releases', :object =>
@releases %td.grid.full_panels{:style => "width: 20%"} Cycles:
%td.grid.full_panels{:style => "width: 20%"} <div id="cycles">
= render :partial => 'cycles', :object => @cycles %tr
%td.grid.full_panels{:style => "width: 20%"}
%td.grid.full_panels{:style => "width: 20%"}
%td.grid.full_panels{:style => "width: 20%"} =submit_tag "Submit"
= javascript_include_tag "pages/ic" partials code : = select_tag
"releases",options_from_collection_for_select(releases,"id","name",params[:releases])

Jquery: //change the releases drop down based on the selction of the
projects drop down.

$('.update_releases').live("change", function()
{ $.ajaxSetup({beforeSend: function(xhr) {xhr.setRequestHeader("X-
CSRF-Token", $("meta[name='csrf-token']").attr("content")); }}); var
project_id=($(this).val()); $.post('/reports/update_releases',
{project_id: project_id}); return false; }) I am getting an error
element doesn't support this property" as a pop up on chaning the
selection in the drop down box. Please help me out here.