Error with custom page

[The-Ensemble]

I created a custom page and I got a problem when trying to make it looks integrated into the USERCP.

The section its having problems with.

PHP Code:

$navbits = array();
// change the line below to contain whatever you want to show in the navbar (title of your custom page)
$navbits[$parent] = 'Custom Page ';


    // sets the area discription, feel free to change
    $navbits[''] = "Custom Page";
    // sets shell template
    $shelltemplatename = 'USERCP_SHELL';



$navbits = construct_usercp_nav("$navbits");
eval('$navbar = "' . fetch_template('navbar') . '";');

// change the line below to contain the name of the actual main output template used in your script
eval('print_output("' . fetch_template('customtemp1') . '");'); 


Its says the problem is "construct_usercp_nav("$navbits")" Is this not a correct function or did I do something else wrong with the coding?