Drupal 7 programmatically create webform components - drupal-7

Question

I've followed this great document which successfully creates a webform and associated components.
I am trying to adjust the code so it works for existing webforms instead of creating new ones.
My code is as follows:
$nid = 12;
$node = node_load(12);
// Create the webform components.
$components = array(
array(
'name' => 'Gender',
'form_key' => 'gender',
'type' => 'select',
'mandatory' => 1,
'weight' => 0,
'pid' => 0,
'extra' => array(
'title_display' => 'inline',
'private' => 0,
'items' => "Mrs|Mrs\nMiss|Miss\nMr|Mr",
'aslist' => 1,
),
),
);
// Setup notification email.
$emails = array(
array(
'email' => 'somebody#example.tld',
'subject' => 'default',
'from_name' => 'default',
'from_address' => 'default',
'template' => 'default',
'excluded_components' => array(),
),
);
// Attach the webform to the node.
$node->webform = array(
'confirmation' => '',
'confirmation_format' => NULL,
'redirect_url' => '<confirmation>',
'status' => '1',
'block' => '0',
'teaser' => '0',
'allow_draft' => '0',
'auto_save' => '0',
'submit_notice' => '1',
'submit_text' => '',
'submit_limit' => '-1', // User can submit more than once.
'submit_interval' => '-1',
'total_submit_limit' => '-1',
'total_submit_interval' => '-1',
'record_exists' => TRUE,
'roles' => array(
0 => '1', // Anonymous user can submit this webform.
),
'emails' => $emails,
'components' => $components,
);
// Save the node.
node_save($node);
When I attempt to execute my code I get the following error:
Error message SQLSTATE[23000]: Integrity constraint violation: 1048 Column 'nid' cannot be null

Answer 1

First try to print all the available values of $node.
echo "<pre>";
print_r($node);
echo "</pre>"'
exit;
check that you are getting value for $node[nid] or not.