title: Fatal error: Unsupported operand types in /includes/theme.inc on line 1075
body: <p>I am trying to convert Drupal6 theme to Drupal7 and I tried to make the necessary changes.
  But I am getting the error 
  <strong>Fatal error: Unsupported operand types in /includes/theme.inc on line 1075</strong>
  The line 1075 is  <strong>$variables += $info['variables'];</strong></p>
  
  <p>My template.php file is as follows </p>
  
  <pre><code>function template_preprocess_search_theme_form(&amp;$variables) {
    $variables['search'] = array();
    $hidden = array();
    // Provide variables named after form keys so themers can print each element independently.
    foreach (element_children($variables['form']) as $key) {
      $type = $variables['form'][$key]['#type'];
      if ($type == 'hidden' || $type == 'token') {
        $hidden[] = drupal_render($variables['form'][$key]);
      }
      else {
        $variables['search'][$key] = drupal_render($variables['form'][$key]);
      }
    }
    // Hidden form elements have no value to themers. No need for separation.
    $variables['search']['hidden'] = implode($hidden);
    // Collect all form elements to make it easier to print the whole form.
    $variables['search_form'] = implode($variables['search']);
  }
  
  
  
  function template_breadcrumb($variables) {
    $breadcrumb = $variables['breadcrumb'];
  
    if (!empty($breadcrumb)) {
      // Provide a navigational heading to give context for breadcrumb links to
      // screen-reader users. Make the heading invisible with .element-invisible.
      $output = '&lt;h2 class="element-invisible"&gt;' . t('You are here') . '&lt;/h2&gt;';
  
      $output .= '&lt;div class="breadcrumb"&gt;' . implode(' » ', $breadcrumb) . '&lt;/div&gt;';
      return $output;
    }
  }
  
      function template_node_submitted(&amp;$variables){
        return t('By !username on @datetime', array(
            '!username' =&gt; theme('username', $variables['node']),
            '@datetime' =&gt; format_date($variable['node']-&gt;created),
        ));
      }
  
  
  
  
      function template_preprocess_page(&amp;$variables){
        $search_box = drupal_render(drupal_get_form('search_form'));
         `enter code here`$variables['search_box'] = $search_box;
        }
  </code></pre>
  
  <p>Please help me in finding the error. As I m quite new to Drupal I am not able to debug it.</p>