diff --git a/includes/webform.components.inc b/includes/webform.components.inc
index 833aad1..df0a711 100644
--- a/includes/webform.components.inc
+++ b/includes/webform.components.inc
@@ -714,7 +714,7 @@ function webform_component_insert(&$component) {
     ->fields(array(
       'nid' => $component['nid'],
       'cid' => $component['cid'],
-      'pid' => $component['pid'],
+      'pid' => !empty($component['pid']) ? $component['pid'] : NULL,
       'form_key' => $component['form_key'],
       'name' => $component['name'],
       'type' => $component['type'],
diff --git a/webform.install b/webform.install
index 333ef4b..22c2444 100644
--- a/webform.install
+++ b/webform.install
@@ -136,7 +136,7 @@ function webform_schema() {
         'type' => 'int',
         'size' => 'small',
         'unsigned' => TRUE,
-        'not null' => TRUE,
+        'not null' => FALSE,
         'default' => 0,
       ),
       'form_key' => array(
@@ -1330,3 +1330,18 @@ function webform_update_7404() {
     _webform_delete_file(NULL, array($fid));
   }
 }
+
+/**
+ * Make webform_component.pid field nillable.
+ */
+function webform_update_7405() {
+  $webform_component_pid_spec = array(
+    'description' => 'If this component has a parent fieldset, the cid of that component.',
+    'type' => 'int',
+    'size' => 'small',
+    'unsigned' => TRUE,
+    'not null' => FALSE,
+    'default' => 0,
+  );
+  db_change_field('webform_component', 'pid', 'pid', $webform_component_pid_spec);
+}
\ No newline at end of file