Edit not working with named routes

HELP! I'm a relatively new rails user and I'm stuck. I'm trying to build a relatively simple blog and I decided that I liked the way named routes look in the code. So I added

map.resources :posts

to my routes.db file. I then went through and updated my controller to take advantage of the named routes that were generated. I also updated all of my views and everything was working nicely. Except when I try to edit an existing post. For some reason it just doesn't want to do anything. Below are the relevant (I think) parts of the PostsController:

class PostsController < ApplicationController   layout "blog"   before_filter :login_required, :except => [:index, :show]   before_filter :find_post, :except => [:index, :new, :create]

  def edit   end

  def update     if @post.update_attributes(params[:post])       flash[:notice] = "Post Updated"       redirect_to post_url(@post)     else       render edit_post_url     end   end

  protected

  def find_post     @post = Post.find(params[:id])   end end

Here is edit.hrtml

<h1>New Post</h1> <% form_for(:post, @post, :url => post_url(@post), :html => {:method => 'put'}) do |f| %>   <%= render :partial => "form", :object => f %> <% end %>

And the form partial...

<p>     <label for='post_title'>Title</label><br />     <%= form.text_field :title %> </p> <p>     <label for='post_permalink'>Permalink</label><br />     <%= form.text_field :permalink %> </p> <p>     <label for='post_abstract'>Abstract</label><br />     <%= form.text_area :abstract %> </p> <p>     <label for='post_body'>Body</label><br />     <%= form.text_area :body %> </p> <p>     <%= submit_tag %> </p>

Have I done something stupid? I get the feeling I probably have and it's making the edits not work.