Newbie Help (No Method Error)

I am following the “Agile Web Development with Rails” and I have decided
to deviate from the book a bit to discover Rails plugins.

I have set up my app to use “paperclip” to size my photos. I have
managed to get the app working on part of my application.

But...Im getting this error.

NoMethodError in Store#index
You have a nil object when you didn't expect it!
The error occurred while evaluating nil.photo

Extracted source (around line #5):

This is my code:

<h1>New Products on Display</h1>

<% for product in @products -%>

  <div class="entry">

    <%= image_tag @product.photo.url ( :small) %>
   <---- (error here)
    <h3><%=h product.title %></h3>

    <%= product.description %>

    <div class="price-line">

    <span class="price"><%= number_to_currency(product.price) %></span>

    <%= button_to "Add to Cart" %>

    </div>

  </div>

<% end %>

This is my first post: Let me know if you guys need more information.
Thanks for the help.

I am following the “Agile Web Development with Rails” and I have
decided
to deviate from the book a bit to discover Rails plugins.

I have set up my app to use “paperclip” to size my photos. I have
managed to get the app working on part of my application.

But...Im getting this error.

NoMethodError in Store#index
You have a nil object when you didn't expect it!
The error occurred while evaluating nil.photo

Extracted source (around line #5):

This is my code:

<h1>New Products on Display</h1>

<% for product in @products -%>

<div class="entry">

   <%= image_tag @product.photo.url ( :small) %>

@product should be product without the @.