FormBuilder upgrade 0.14.0 -> 0.17.1

Hello everybody, I've got a Web Application that is working fine with FormBuilder 0.14.0. Now, I'm trying to upgrade from FormBuilder 0.14.0 -> 0.17.1 but I get the following error message : -- Warning: Call-time pass-by-reference has been deprecated - argument passed by value; If you would like to pass it by reference, modify the declaration of call_user_func(). If you would like to enable call-time pass-by-reference, you can set allow_call_time_pass_reference to true in your INI file. However, future versions may not support this any longer. in C:\Documents and Settings\TBA\My Documents\www\trame\pear\DB\DataObject\FormBuilder.php on line 2090 -- Can anybody please explain me what is happening? I really can't figure out what's wrong. Which part of my code must be adapted to allow me to upgrade from 0.14.0 to 0.17.1? Thanks in advance for your help, it will be much-much appreciated. Thomas Balthazar. P.S. : the reason why I want to upgrade is : - I use crossLinks to display m:n relationship in my forms - I configure it to display values in a <select> --> I would like to be able to modify the size of the <select> : when there is a lot of values, I would like them to be displayed in a 5 lines <select> with a scrollbar (I really really need it!). Will the new Collapse option help me to do that?