diff --git a/gulliver/system/class.headPublisher.php b/gulliver/system/class.headPublisher.php
index 4bd0a9dce..8eaa4164f 100644
--- a/gulliver/system/class.headPublisher.php
+++ b/gulliver/system/class.headPublisher.php
@@ -314,11 +314,13 @@ class headPublisher {
 */
     // Load external/plugin css
     // NOTE is necesary to move this to decorator server
+    if(class_exists('PMPluginRegistry')){
     $oPluginRegistry = & PMPluginRegistry::getSingleton ();
     $registeredCss=$oPluginRegistry->getRegisteredCss();
     foreach($registeredCss as $cssFile){
       $script .= "  <link rel='stylesheet' type='text/css' href='" . $cssFile->sCssFile . ".css' />\n";
     }
+    }
     
     return $script;
   }