diff --git a/includes/FeedsImporter.inc b/includes/FeedsImporter.inc
index 1e69f2e..afd8964 100644
--- a/includes/FeedsImporter.inc
+++ b/includes/FeedsImporter.inc
@@ -191,7 +191,7 @@ class FeedsImporter extends FeedsConfigurable {
     foreach ($plugin_types as $type => $plugin_label) {
       // Check if plugin exists.
       $plugin = feeds_plugin($this->config[$type]['plugin_key'], $this->id);
-      if (!($plugin instanceof FeedsMissingPlugin)) {
+      if ($plugin instanceof FeedsMissingPlugin) {
         $errors[] = t('The plugin %plugin is unavailable.', array('%plugin' => $this->config[$type]['plugin_key']));
         continue;
       }