diff --git a/dibi/Nette/DibiNettePanel.php b/dibi/Nette/DibiNettePanel.php
index d533b8d8..1bc12975 100644
--- a/dibi/Nette/DibiNettePanel.php
+++ b/dibi/Nette/DibiNettePanel.php
@@ -53,12 +53,12 @@ class DibiNettePanel extends DibiObject implements IBarPanel
 			class_alias('Nette\Diagnostics\Debugger', 'NDebugger'); // PHP 5.2 code compatibility
 		}
 		if (is_callable('NDebugger::enable')) {
-			NDebugger::$bar->addPanel($this);
-			NDebugger::$blueScreen->addPanel(array($this, 'renderException'), __CLASS__);
+			NDebugger::$bar && NDebugger::$bar->addPanel($this);
+			NDebugger::$blueScreen && NDebugger::$blueScreen->addPanel(array($this, 'renderException'), __CLASS__);
 			$connection->onEvent[] = array($this, 'logEvent');
 		} elseif (is_callable('Debugger::enable')) {
-			Debugger::$bar->addPanel($this);
-			Debugger::$blueScreen->addPanel(array($this, 'renderException'), __CLASS__);
+			Debugger::$bar && Debugger::$bar->addPanel($this);
+			Debugger::$blueScreen && Debugger::$blueScreen->addPanel(array($this, 'renderException'), __CLASS__);
 			$connection->onEvent[] = array($this, 'logEvent');
 		}
 	}