diff --git a/server/lib/classes/addon_installer.inc.php b/server/lib/classes/addon_installer.inc.php
index 07301f34f73e46a45effbab6a5fc76b23d9cc7a9..3a108e8bbb2f128883ec03c97cbc54c5589bd760 100644
--- a/server/lib/classes/addon_installer.inc.php
+++ b/server/lib/classes/addon_installer.inc.php
@@ -54,6 +54,8 @@ class addon_installer {
 	 * @throws AddonInstallerValidationException
 	 */
 	private function validatePackage($path) {
+		global $app;
+		
 		$app->log('Validating extracted addon at ' . $path, 0, false);
 		
 		if(!is_dir($path)) {
diff --git a/server/lib/classes/ispconfig_addon_installer_base.inc.php b/server/lib/classes/ispconfig_addon_installer_base.inc.php
index 2aa2d184ab4a94d6de27bf453bcf1ba7ee41e2f4..5767864c2550bd10c5dc39a4141c48808ba88d0e 100644
--- a/server/lib/classes/ispconfig_addon_installer_base.inc.php
+++ b/server/lib/classes/ispconfig_addon_installer_base.inc.php
@@ -34,7 +34,7 @@ class ispconfig_addon_installer_base {
 	}
 	
 	protected function copyInterfaceFiles() {
-		global $conf;
+		global $app, $conf;
 		
 		$app->log('Copying interface files.', 0, false);
 		$install_dir = realpath($conf['rootpath'] . '/..');
@@ -56,7 +56,7 @@ class ispconfig_addon_installer_base {
 	}
 	
 	protected function copyServerFiles() {
-		global $conf;
+		global $app, $conf;
 		
 		$app->log('Copying server files.', 0, false);
 		
@@ -169,6 +169,8 @@ class ispconfig_addon_installer_base {
 	public function onBeforeInstall() { }
 	
 	public function onInstall() {
+		global $app;
+		
 		$app->log('Running onInstall()', 0, false);
 		$this->copyAddonFiles();
 		$this->copyInterfaceFiles();
@@ -182,6 +184,8 @@ class ispconfig_addon_installer_base {
 	public function onBeforeUpdate() { }
 	
 	public function onUpdate() {
+		global $app;
+
 		$app->log('Running onUpdate()', 0, false);
 		$this->copyAddonFiles();
 		$this->copyInterfaceFiles();