Error while upgrading from Drupal 6 to Drupal 7

I get the following error while upgrading from D6 to D7:

An error occurred.
Path: http://test.local/update.php?id=2&op=do
Message: FieldException: Attempt to create an instance of a field that doesn't exist. in field_create_instance() (line 433 of E:\www\test\modules\field\field.crud.inc).

I set $conf['blocked_ips'] = array(); in settings.php to avoid #517742: Upgrade failing if blocked_ips doesn't exist. Attached you can find the (test) D6 database from which I try to upgrade.

My system specs (Windows Vista, PHP Memory limit: 256M, all green lights in the status report):

###### ApacheFriends XAMPP (Basispaket) version 1.7.1 ######

  + Apache 2.2.11
  + MySQL 5.1.33 (Community Server)
  + PHP 5.2.9 + PEAR
  + XAMPP Control Version 2.5
  + XAMPP CLI Bundle 1.3
  + XAMPP Security 1.0	
  + SQLite 2.8.15
  + OpenSSL 0.9.8i
  + phpMyAdmin 3.1.3.1
  + ADOdb 5.06a
  + Zend Optimizer 3.3.0 
  + eAccelerator 0.9.5.3 for PHP 5.2.9 (but not activated in the php.ini)