you need a line that says core="6.x" in the info file for drupal 6 modules..
you will also need to give the SKU a default value, as it's a required field. Though you could probably set the #required attribute to FALSE.
my_module.info:
; $Id$
name = My Module
description = My customizations to Ubercart
package = Custom
core = "6.x"
dependencies[] = uc_cart
my_module.module:
<?php
// $Id$
/**
* @file
* Module to hold my customizations to Ubercart
*/
/**
* Implementation of hook_form_alter()
*/
function my_module_form_alter(&$form, $form_state, $form_id) {
if ($form_id == 'product_node_form') {
$form['base']['model']['#type'] = 'hidden';
$form['base']['model']['#default_value'] = 'default value';
// Choose which method you want to use, the above line, or comment it out and uncomment the following line:
// $form['base']['model']['#required'] = FALSE;
}
}