Cannot get Observer to trigger

[D-man]

Using v1.3.9h

I am trying to learn how to use Observers, I've followed examples and searched forum but I cannot find what I'm doing wrong.

I have class.mycheckoutobs.php located at /includes/classes/observers

<?php
 class mycheckoutobs extends base {
   function mycheckoutobs() {
     $this->attach($this, array('NOTIFY_CHECKOUT_PROCESS_AFTER_SEND_ORDER_EMAIL'));
   }
   function update(&$callingClass, $notifier, $paramsArray) {
    $filename = 'test.txt'; 
    $somecontent = "Add this to the file\n"; 
    echo "Current directory is " . getcwd();
    // Let's make sure the file exists and is writable first. 
    if (is_writable($filename)) { 
    
        // In our example we're opening $filename in append mode. 
        // The file pointer is at the bottom of the file hence 
        // that's where $somecontent will go when we fwrite() it. 
        if (!$handle = fopen($filename, 'a')) { 
         print "Cannot open file ($filename)"; 
         exit; 
        } 
    
        // Write $somecontent to our opened file. 
        if (!fwrite($handle, $somecontent)) { 
        print "Cannot write to file ($filename)"; 
        exit; 
        } 
         
        print "Success, wrote ($somecontent) to file ($filename)"; 
         
        fclose($handle); 
                 
    } else { 
        print "The file $filename is not writable"; 
    } 
   }
 }
?>

I have config.mycheckoutobs.php at /includes/auto_loaders

<?php

$autoLoadConfig[10][] = array('autoType'=>'class',
                              'loadFile'=>'observers/class.mycheckoutobs.php');
$autoLoadConfig[90][] = array('autoType'=>'classInstantiate',
                              'className'=>'mycheckoutobs',
                              'objectName'=>'mycheckoutobs');
?>

This is just a test to learn. Anyone see what is wrong?