Dynic menu has not visible output

I create a dynamic menu with just one menu element.
OnApplicationInit:
$menuName=‘test dyn Menu’;
sc_appmenu_reset($menuName);
sc_appmenu_create($menuName);
$itemId=“1”;
$parentId="";
$label=“Menu label”;
$appName=“sec_login”;
$appParam="";
$icon="";
$appHint=“Ein Hint für diesen Menu Eintrag”;
$appTarget="_self";
sc_appmenu_add_item($menuName,$itemId,$parentId,$label,$appName,$appParam,$icon,$appHint,$appTarget);
I use the tree_menu template

It just shows an empty screen.
Can somebody help?