diff --git a/readme.txt b/README.txt
similarity index 79%
rename from readme.txt
rename to README.txt
index 16f89eb9749254524e6333df8f5bc5cf69b3e8cb..1c46d1e607130881f58c12a271d504b9dbdd8ba7 100644
--- a/readme.txt
+++ b/README.txt
@@ -21,7 +21,20 @@ module name.
 Installation:
 
 Install Views
-Install Commerce
+Install Commerce (& commerce modules).
+Commerce Popular Modules depends on the following Commerce modules:
+commerce_ui
+commerce_cart
+commerce_checkout
+commerce_customer
+commerce_line_item
+commerce_order
+commerce_payment
+commerce_price
+commerce_product
+commerce_product_reference
+commerce_product_pricing
+
 Install Commerce Popular Products
 Place the block wherever you want it
 Set up your products & product displays.
diff --git a/commerce_popular_products.info b/commerce_popular_products.info
index 9845004375f6219c6cedd45c215388bc6cfb5a75..9173432e7e71c5cb882bde5ce4719facc4976a68 100644
--- a/commerce_popular_products.info
+++ b/commerce_popular_products.info
@@ -5,3 +5,14 @@ core = "7.x"
 package = Commerce (Contrib)
 dependencies[] = commerce
 dependencies[] = views
+dependencies[] = commerce_ui
+dependencies[] = commerce_cart
+dependencies[] = commerce_checkout
+dependencies[] = commerce_customer
+dependencies[] = commerce_line_item
+dependencies[] = commerce_order
+dependencies[] = commerce_payment
+dependencies[] = commerce_price
+dependencies[] = commerce_product
+dependencies[] = commerce_product_reference
+dependencies[] = commerce_product_pricing
diff --git a/commerce_popular_products.module b/commerce_popular_products.module
index 4df68ce24ab136213ff800481320be5149044d27..f3c42267e198e09ce65b3b58ea4e09c0bb623ece 100644
--- a/commerce_popular_products.module
+++ b/commerce_popular_products.module
@@ -199,12 +199,20 @@ function commerce_popular_products_settings_form($form, &$form_state) {
     '#description' => t('The title of the "popular products" block as shown to users.'),
     '#default_value' => $title,
   );
-  $form['product_types'] = array(
-    '#type' => 'checkboxes',
-    '#title' => t('Product Types.'),
-    '#description' => t('Product nodes to include in the popularity check.'),
-    '#default_value' => $products,
-  );
+  if (isset($products)) {
+    $form['product_types'] = array(
+      '#type' => 'checkboxes',
+      '#title' => t('Product Types.'),
+      '#description' => t('Product nodes to include in the popularity check.'),
+      '#default_value' => $products,
+    );
+  }
+  else {
+    $form['product_types'] = array(
+      '#title' => t('Product Types.'),
+      '#markup' => t('<h4>Product types</h4><p>You have not defined any product types. You need to define some first.</p>'),
+    );
+  }
   $product_types = commerce_popular_products_get_product_types();
   $options = array();
   foreach ($product_types as $type) {
@@ -260,6 +268,7 @@ function commerce_popular_products_settings_form_submit($form, &$form_state) {
  * A simple query to return all the Commerce product types in the database.
  */
 function commerce_popular_products_get_product_types() {
+  $names = array();
   $products = commerce_product_types();
   foreach ($products as $item) {
     $names[] = $item['name'];