Call to a member function on a non-object

[etrader]

I'm getting a 'Call to a member function on a non-object' error on line 25. ( I have commented line 25 for you). Any ideas what the problem might be?



class categorygenerator {
var $root_uniqueid = 0,
$max_level = 6,
$data = array(),
$root_start_string = '',
$root_end_string = '',
$parent_start_string = '',
$parent_end_string = '',

$parent_group_start_string = '<ul%s>',
$parent_group_end_string = "</ul>\n",

$child_start_string = '<li%s>',
$child_end_string = "</li>\n",

$spacer_string = '',
$spacer_multiplier = 1;

function categorygenerator($load_from_database = true) {
global $db;
$this->data = array();
$categories_query = "SELECT pagetitle, uniqueid, parentid FROM category WHERE uniqueid = 'uniqueid' ORDER BY parentid, pagetitle";
$categories = $db->Execute($categories_query); // line 25
while (!$categories->EOF) {
$this->data[$categories->fields['parentid']][$categories->fields['uniqueid']] = array('name' => $categories->fields['pagetitle'], 'count' => 0);
$categories->MoveNext();
}
}

[PeejAvery]

Your problem is that $db has not been declared/set as an object. Make sure that it is set AND that it is an object.