drupal 6 upgrade failure due to function being called before sql has happened

I just tried to run the upgrade script on a d6 drupal site & hit a fatal - the call to getModuleUFGroup that happens early in the process requires a schema change that has not yet run.

(NB - I'm going to hack my way past this to see if it completes so am not retaining a database in a state to QA any fixes on this)

SELECT civicrm_uf_group.id, title, created_id, description, civicrm_uf_group.is_active, is_reserved, group_type FROM civicrm_uf_group LEFT JOIN civicrm_uf_join ON (civicrm_uf_group.id = uf_group_id) AND civicrm_uf_group.is_active = 1 WHERE civicrm_uf_join.module = 'User Account' ORDER BY civicrm_uf_join.weight, civicrm_uf_group.title [nativecode=1054 ** Unknown column 'description' in 'field list']
DebugInfo SELECT civicrm_uf_group.id, title, created_id, description, civicrm_uf_group.is_active, is_reserved, group_type FROM civicrm_uf_group LEFT JOIN civicrm_uf_join ON (civicrm_uf_group.id = uf_group_id) AND civicrm_uf_group.is_active = 1 WHERE civicrm_uf_join.module = 'User Account' ORDER BY civicrm_uf_join.weight, civicrm_uf_group.title [nativecode=1054 ** Unknown column 'description' in 'field list']

piece of code it fails on - called by civicrm_user('categories', null, Object(stdClass), '')

function civicrm_categories(&$user) {
if (!civicrm_initialize())

require_once 'CRM/Core/BAO/UFGroup.php';
require_once 'CRM/Core/BAO/UFField.php';

$allUFGroups = CRM_Core_BAO_UFGroup::getModuleUFGroup('User Account');