Index: trunk/core/kernel/event_manager.php
===================================================================
diff -u -r1560 -r2060
--- trunk/core/kernel/event_manager.php	(.../event_manager.php)	(revision 1560)
+++ trunk/core/kernel/event_manager.php	(.../event_manager.php)	(revision 2060)
@@ -194,6 +194,14 @@
 		
 		function registerHook($hookto_prefix, $hookto_special, $hookto_event, $mode, $do_prefix, $do_special, $do_event, $conditional)
 		{
+			if( !$this->Application->getUnitOptions($hookto_prefix) )
+			{
+				if($this->Application->isDebugMode())
+				{
+					trigger_error('Prefix <b>'.$hookto_prefix.'</b> doesn\'t exist when trying to hook from <b>'.$do_prefix.':'.$do_event.'</b>', E_USER_WARNING);
+				}
+				return;
+			}
 			$hookto_prefix_special = rtrim($hookto_prefix.'.'.$hookto_special, '.');
 			if ($mode == hBEFORE) {
 				$this->beforeHooks[strtolower($hookto_prefix_special.'.'.$hookto_event)][] = Array(