Bugs fixed:

* Dont crash or point errors when the default plugin was not yet defined

charts.inc

@@ -161,7 +161,9 @@ function _charts_settings($form_state) {
     '#type'           => 'select',
     '#title'          => t('Chart plugin'),
   );
-  asort($charts_info[$settings['#plugin']]['types']);
+  if (!empty($settings['#plugin'])) {
+    asort($charts_info[$settings['#plugin']]['types']);
+  }
   $form['type'] = array(
     '#default_value'  => empty($settings['#type']) ? '' : $settings['#type'],
     '#options'        => $charts_info[$settings['#plugin']]['types'],

charts.module

@@ -20,13 +20,13 @@
  *   JavaScript external files)
  */
 function charts_chart(&$data) {
-  if (empty($data['#plugin'])) {
-    return '';
-  }
-
   // Get the previously saved data from database
   $settings = variable_get('charts_settings', array());
 
+  if (empty($data['#plugin']) and empty($settings['#plugin'])) {
+    return '';
+  }
+
   // Split the color palette data into inidividual values
   $color_palette = explode(',', ereg_replace('#', '', $settings['#color_palette']));