A product with SKU could not be found. Please check that the product exists or import it first.

I have a problem importing products to product display. I receive error "A product with SKU could not be found. Please check that the product exists or import it first." See error-sku-import.png for error.

Product display is nevertheless imported, but there is no reference to the product. Even if I remove import of the reference field, I receive the same error.

I am importing xml file with Feeds extensible parser.

I use combination of these modules:
Commerce feeds 7.x-1.4
Domain Feeds (Domain Access Entity integration) 7.x-1.4
Feeds 7.x-2.0-beta2+21-dev
Feeds extensible parser 7.x-1.0-beta2+15-dev
Feeds Image Grabber 7.x-1.0-alpha2
Feeds Tamper 7.x-1.1+2-dev

My importer conf:

$feeds_importer = new stdClass();
$feeds_importer->disabled = FALSE; /* Edit this to true to make a default feeds_importer disabled initially */
$feeds_importer->api_version = 1;
$feeds_importer->id = 'pnevmatike_opisi';
$feeds_importer->config = array(
  'name' => 'Osebne pnevmatike - opisi',
  'description' => 'Osebne pnevmatike - opisi',
  'fetcher' => array(
    'plugin_key' => 'FeedsHTTPFetcher',
    'config' => array(
      'auto_detect_feeds' => FALSE,
      'use_pubsubhubbub' => FALSE,
      'designated_hub' => '',
      'request_timeout' => NULL,
      'auto_scheme' => 'http',
      'accept_invalid_cert' => FALSE,
    ),
  ),
  'parser' => array(
    'plugin_key' => 'FeedsExXml',
    'config' => array(
      'context' => array(
        'value' => 'ROOT/ELEMENT',
      ),
      'sources' => array(
        'sku' => array(
          'name' => 'sku',
          'value' => 'SIFRA',
          'raw' => 0,
          'inner' => 0,
          'debug' => 1,
          'weight' => '1',
        ),
        'title' => array(
          'name' => 'title',
          'value' => 'NAZIV',
          'raw' => 0,
          'inner' => 0,
          'debug' => 0,
          'weight' => '2',
        ),
        'kategorija' => array(
          'name' => 'kategorija',
          'value' => 'KATEGORIJA',
          'raw' => 0,
          'inner' => 0,
          'debug' => 0,
          'weight' => '3',
        ),
      ),
      'display_errors' => 0,
      'debug_mode' => 0,
      'source_encoding' => array(
        0 => 'auto',
      ),
      'use_tidy' => FALSE,
    ),
  ),
  'processor' => array(
    'plugin_key' => 'FeedsNodeProcessor',
    'config' => array(
      'expire' => '-1',
      'author' => '1',
      'authorize' => 1,
      'mappings' => array(
        0 => array(
          'source' => 'sku',
          'target' => 'guid',
          'unique' => 1,
          'language' => 'und',
        ),
        1 => array(
          'source' => 'title',
          'target' => 'title',
          'unique' => 0,
          'language' => 'und',
        ),
        2 => array(
          'source' => 'kategorija',
          'target' => 'field_categories',
          'term_search' => '0',
          'autocreate' => 1,
          'language' => 'und',
        ),
        3 => array(
          'source' => 'Blank source 1',
          'target' => 'domains:2',
          'unique' => FALSE,
          'language' => 'und',
        ),
        4 => array(
          'source' => 'sku',
          'target' => 'field_product:sku',
          'unique' => FALSE,
          'language' => 'und',
        ),
      ),
      'insert_new' => '1',
      'update_existing' => '2',
      'update_non_existent' => 'delete',
      'input_format' => 'full_html',
      'skip_hash_check' => 1,
      'bundle' => 'product_display',
      'language' => 'sl',
    ),
  ),
  'content_type' => '',
  'update' => 0,
  'import_period' => '-1',
  'expire_period' => 3600,
  'import_on_create' => 1,
  'process_in_background' => 0,
);

Thanks in advance for your help.