MPTtree, Hieararchical trees in a database table

[eluser]Base Willy[/eluser]
Hi!

Trying to get it work but all i see at tree_admin is a horizontal line and tree icon. And there is nothing to do.. Screenshot

Before that I had an error

Code:

Fatal error: Cannot pass parameter 1 by reference in D:\wamp\www\pitomec\system\application\models\mpttree.php on line 391

and fixed it by changing

Code:

function debug_message(&$message){

to

Code:

function debug_message($message){