using CMS to open page - php

Question

this is the index.php
<table align="center" border="0" cellpadding="0" cellspacing="0">
<tbody>
<?php include 'header.php'; ?>
<tr>
<td class="row_2">
<!-- header_eof //-->
<!-- body //-->
<table class="main_table" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<?php
if($cond)
include 'left.php'; ?>
<!-- body_text //-->
<?php get_page(); ?>
<!-- body_text_eof //-->
<?php
if($cond)
include 'right.php'; ?>
</tr>
<tr>
<?php
if(!$cond)
include 'contents/contact_us.php';?>
</tr>
</tbody>
</table>
<!-- body_eof //-->
<!-- footer //-->
</td>
</tr>
<?php include 'footer.php'; ?>
</tbody>
</table>
This is header.php . I have created link from database
<?php
$menus = db_query("select * from menus where type=0 order by weight");
$sr = 0;
while($menu = mysql_fetch_object($menus)) { ?>
<?php if(($sr++) > 0){ ?>
<td class="menu_separator"><img src="<?php echo SROOT;?>images/menu_separator.png" alt="" class="png" width="2" border="0" height="49"></td>
<?php } ?>
<td id="<?php echo get_id($menu->page_name); ?>" <?php echo get_event($menu->page_name); ?> onClick="document.location='<?php echo SROOT . $menu->page_name;?>'" nowrap="nowrap"><?php echo $menu->title; ?></td>
<?php } ?>
this is the get_page function
function get_page() {
$page = arg(0);
$page = (empty($page)) ? 'home' : $page;
$cat = db_query("select * from mb_category where title='".$page."'");
$page = (mysql_num_rows($cat)) ? 'brands' : $page;
include 'contents/'. $page .'.php';
}
I have everything in the right place.The same code is working for my friend but we are unable to understand the problem here. I get error cannot find page. His is working fine.
When i click link it says cannot find page..but his goes to page
Can anyone please help and tell me what i am doing wrong

Answer 1

Edited:
The part I don't understand is this:
$page = arg(0);
$page = (empty($page)) ? 'home' : $page;
$cat = db_query("select * from mb_category where title='".$page."'");
What is "arg(0)?, so how do you get $page?
Ok, I understand this is a drupal function or alike.
But, pls, verify that arg(0) returns sth.
If you are not sure of the path the include is taken, I would change this line:
include 'contents/'. $page .'.php';
for:
include $_SERVER["DOCUMENT_ROOT"]."/contents/'. $page .'.php';