# notice there is no @bid, you passed in the object with the partial => @bid, so you just need the partial file_name bid

<% form_for [picture, bid] do |f| %>
	<%= f.error_messages %>

	<%= f.label :amount %><br />
	<%= f.text_field :amount %>

	<%= f.hidden_field :picture_id, :value => @bid.picture_id %>
	<p>
		<%= f.submit 'bid!' %>
	</p>
<% end %>