Fatal error need help

[msalman]

hey all,

I've a php file and it amkes some quries to database and when i try to run it, it give me following error

Fatal error: Call to a member function on a non-object in /home/content/I/s/l/mydomain/html/forums/includes/myfile.php on line 5

this is the code that i've so far in myfile.php

<?php
// i'm calling this function in another php file
     function displayIndex() 
     {
// this is line 5
        $query = $db->query_read("SELECT DISTINCT chpNo_en, chpName_en FROM quran_en ORDER BY chpNo_en ASC"); 

        $indexArray;
        $cnt = 0;

        while ($row = $db->fetch_array($query)) {

              $indexArray[$cnt]['chpNo'] = $row['chpNo_en'];
              $indexArray[$cnt]['chpName'] = $row['chpName_en'];

              $verses =  $db->query_read_first("SELECT COUNT(ayatNo_en) AS verses FROM quran_en WHERE chpNo_en=". $row['chpNo_en']);

              while ($verse = $db->fetch_array($verses)) {
                  $indexArray[$cnt]['verses'] = $verse['verses'];
              }

              $cnt++;
        }
        $cnt = 0;
        $query = $db->query_read("SELECT DISTINCT chpName_ar, chpNo_ar FROM quran_ar ORDER BY chpNo_ar ASC");
        $array;

        while ($row = $db->fetch_array($query)) {
              $array[$cnt] = $row['chpName_ar'];
              $cnt++;
        }

        for ($i = 0; $i < $cnt; $i++) {
              if ($i <  38) {
                 $indexArray[$i]['chpName'] = $indexArray[$i]['chpName'] . $array[$i];
              } else if ($i >= 38) {
                 $indexArray[$i]['chpName'] = $indexArray[$i]['chpName'] . $array[$i+1];
              }
        }

        return $indexArray();
     }
?>