XML output

[micmac]

Hi all,
I'm attempting to generate XML output via a query. I'm wanting to generate a parentID style tree structure.
I've successfully created a recursive function to output the data however am having difficulty generating the XML side of things. This is what i have so far:

<?
function maketree($rootcatid,$level) 
{ 
   mysql_connect("localhost","root","");
   mysql_select_db("theodore_alexander");

   $sql="select cat_id,cat_name 
           from categories 
           where cat_parent=$rootcatid 
           order by cat_name"; 

 //echo "$sql<br>\n"; 
 $result=mysql_query($sql);

 while (list($DBcatid,$DBcatname)=mysql_fetch_row($result)) 
 { 
   $width=($level+1)*24;
   echo $DBcatid." ".$rootcatid; 
   $display="<img src=e.gif width=$width height=12>"; 
   $display.="$DBcatname"; 
   $display.="<br>\n"; 
   echo $display; 
   maketree($DBcatid,$level+1); 
 } 

   }

$xml_output = "<?xml version=\"1.0\"?>\n"; 
$xml_output .= "<node label='categories'>\n";   

echo $xml_output;  

maketree(0,0);
echo "</node>";
?>

I need the output to resemble the following:

<?xml version="1.0" encoding="iso-8859-1"?>
<node label="categories">
    <node label="Cat 1"/>
    <node label="Cat 2">
        <node label="Cat 2.1">
            <node label="Cat 2.4.1"/>
        </node>
    </node>
    <node label="Cat 3"/>
    <node label="Cat 4"/>
</node>

The DB looks like:

cat_id   cat_parent   cat_name
1        0            Cat 1
2        0            Cat 2
3        0            Cat 3
4        2            Cat 2.1
5        0            Cat 4
6        4            Cat 2.4.1

Cheers

[Houdini]

First change this

<?
function maketree($rootcatid,$level) 

to this

<?php
function maketree($rootcatid,$level) 

then tell us what happens, you can not use short tags mixed with XML

[micmac]

Thanks for the prompt reply, i've amendended my code to include your suggestion however the issue i am having is outputing the nodes correctly.

[micmac]

Still no luck with this one. Can anyone shed more light on the issue?