Fatal error: Cannot use string offset as an array

The exported view:

$view = new view;
$view->name = 'Elementi_Ordnen';
$view->description = 'Inhaltsverzeichnis ordnen';
$view->tag = '';
$view->view_php = '';
$view->base_table = 'node';
$view->is_cacheable = FALSE;
$view->api_version = 2;
$view->disabled = FALSE; /* Edit this to true to make a default view disabled initially */
$handler = $view->new_display('default', 'Defaults', 'default');
$handler->override_option('relationships', array(
  'nid' => array(
    'label' => 'Book parent',
    'required' => 0,
    'id' => 'nid',
    'table' => 'book_parent',
    'field' => 'nid',
    'override' => array(
      'button' => 'Override',
    ),
    'relationship' => 'none',
  ),
));
$handler->override_option('fields', array(
  'title' => array(
    'label' => 'Titel',
    'alter' => array(
      'alter_text' => 0,
      'text' => '',
      'make_link' => 0,
      'path' => '',
      'link_class' => '',
      'alt' => '',
      'prefix' => '',
      'suffix' => '',
      'target' => '',
      'help' => '',
      'trim' => 0,
      'max_length' => '',
      'word_boundary' => 1,
      'ellipsis' => 1,
      'strip_tags' => 0,
      'html' => 0,
    ),
    'empty' => '',
    'hide_empty' => 0,
    'empty_zero' => 0,
    'link_to_node' => 1,
    'exclude' => 0,
    'id' => 'title',
    'table' => 'node',
    'field' => 'title',
    'override' => array(
      'button' => 'Übersteuern',
    ),
    'relationship' => 'none',
  ),
  'weight' => array(
    'label' => 'Weight',
    'alter' => array(
      'alter_text' => 0,
      'text' => '',
      'make_link' => 0,
      'path' => '',
      'link_class' => '',
      'alt' => '',
      'prefix' => '',
      'suffix' => '',
      'help' => '',
      'trim' => 0,
      'max_length' => '',
      'word_boundary' => 1,
      'ellipsis' => 1,
      'strip_tags' => 0,
      'html' => 0,
    ),
    'set_precision' => FALSE,
    'precision' => 0,
    'decimal' => '.',
    'separator' => ',',
    'prefix' => '',
    'suffix' => '',
    'exclude' => 0,
    'id' => 'weight',
    'table' => 'book_menu_links',
    'field' => 'weight',
    'relationship' => 'none',
  ),
  'nid_1' => array(
    'label' => 'Parent Nid',
    'alter' => array(
      'alter_text' => 0,
      'text' => '',
      'make_link' => 0,
      'path' => '',
      'link_class' => '',
      'alt' => '',
      'prefix' => '',
      'suffix' => '',
      'help' => '',
      'trim' => 0,
      'max_length' => '',
      'word_boundary' => 1,
      'ellipsis' => 1,
      'strip_tags' => 0,
      'html' => 0,
    ),
    'link_to_node' => 0,
    'exclude' => 0,
    'id' => 'nid_1',
    'table' => 'node',
    'field' => 'nid',
    'override' => array(
      'button' => 'Override',
    ),
    'relationship' => 'nid',
  ),
  'timestamp' => array(
    'label' => 'Aktualisiert',
    'alter' => array(
      'alter_text' => 0,
      'text' => '',
      'make_link' => 0,
      'path' => '',
      'link_class' => '',
      'alt' => '',
      'prefix' => '',
      'suffix' => '',
      'target' => '',
      'help' => '',
      'trim' => 0,
      'max_length' => '',
      'word_boundary' => 1,
      'ellipsis' => 1,
      'strip_tags' => 0,
      'html' => 0,
    ),
    'empty' => '',
    'hide_empty' => 0,
    'empty_zero' => 0,
    'date_format' => 'custom',
    'custom_date_format' => 'd.m.Y H:i',
    'exclude' => 0,
    'id' => 'timestamp',
    'table' => 'node_revisions',
    'field' => 'timestamp',
    'override' => array(
      'button' => 'Übersteuern',
    ),
    'relationship' => 'none',
  ),
  'name' => array(
    'label' => 'von',
    'alter' => array(
      'alter_text' => 0,
      'text' => '',
      'make_link' => 0,
      'path' => '',
      'link_class' => '',
      'alt' => '',
      'prefix' => '',
      'suffix' => '',
      'target' => '',
      'help' => '',
      'trim' => 0,
      'max_length' => '',
      'word_boundary' => 1,
      'ellipsis' => 1,
      'strip_tags' => 0,
      'html' => 0,
    ),
    'empty' => '',
    'hide_empty' => 0,
    'empty_zero' => 0,
    'link_to_user' => 0,
    'overwrite_anonymous' => 0,
    'anonymous_text' => '',
    'exclude' => 0,
    'id' => 'name',
    'table' => 'users',
    'field' => 'name',
    'override' => array(
      'button' => 'Übersteuern',
    ),
    'relationship' => 'none',
  ),
  'nid' => array(
    'label' => '',
    'alter' => array(
      'alter_text' => 1,
      'text' => 'bearbeiten',
      'make_link' => 1,
      'path' => 'node/[nid]/edit',
      'link_class' => '',
      'alt' => 'Seite bearbeiten',
      'prefix' => '',
      'suffix' => '',
      'target' => '',
      'help' => '',
      'trim' => 0,
      'max_length' => '',
      'word_boundary' => 1,
      'ellipsis' => 1,
      'strip_tags' => 0,
      'html' => 0,
    ),
    'empty' => '',
    'hide_empty' => 0,
    'empty_zero' => 0,
    'link_to_node' => 0,
    'exclude' => 0,
    'id' => 'nid',
    'table' => 'node',
    'field' => 'nid',
    'override' => array(
      'button' => 'Übersteuern',
    ),
    'relationship' => 'none',
  ),
));
$handler->override_option('sorts', array(
  'weight_1' => array(
    'order' => 'ASC',
    'id' => 'weight_1',
    'table' => 'book_menu_links',
    'field' => 'weight',
    'override' => array(
      'button' => 'Override',
    ),
    'relationship' => 'none',
  ),
  'p' => array(
    'order' => 'ASC',
    'id' => 'p',
    'table' => 'book_menu_links',
    'field' => 'p',
    'override' => array(
      'button' => 'Override',
    ),
    'relationship' => 'none',
  ),
));
$handler->override_option('arguments', array(
  'p' => array(
    'default_action' => 'default',
    'style_plugin' => 'default_summary',
    'style_options' => array(),
    'wildcard' => 'all',
    'wildcard_substitution' => 'Alle',
    'title' => '',
    'breadcrumb' => '',
    'default_argument_type' => 'node',
    'default_argument' => '',
    'validate_type' => 'node',
    'validate_fail' => 'not found',
    'id' => 'p',
    'table' => 'draggableviews_book_book_parent',
    'field' => 'p',
    'validate_user_argument_type' => 'uid',
    'validate_user_roles' => array(
      '2' => 0,
      '3' => 0,
      '4' => 0,
    ),
    'override' => array(
      'button' => 'Übersteuern',
    ),
    'relationship' => 'none',
    'default_options_div_prefix' => '',
    'default_argument_user' => 0,
    'default_argument_fixed' => '32',
    'default_argument_php' => '',
    'validate_argument_node_type' => array(
      'elementi' => 'elementi',
      'diashow' => 0,
      'event' => 0,
      'gallery_romer' => 0,
      'home' => 0,
      'page' => 0,
      'press' => 0,
      'profile' => 0,
      'profile_cv' => 0,
      'publication' => 0,
      'webform' => 0,
    ),
    'validate_argument_node_access' => 1,
    'validate_argument_nid_type' => 'nid',
    'validate_argument_vocabulary' => array(
      '1' => 0,
      '2' => 0,
    ),
    'validate_argument_type' => 'tid',
    'validate_argument_transform' => 0,
    'validate_user_restrict_roles' => 0,
    'validate_argument_php' => '',
    'user_argument_type' => '',
    'restrict_user_roles' => 0,
    'user_roles' => array(),
  ),
));
$handler->override_option('access', array(
  'type' => 'role',
  'role' => array(
    '3' => 3,
  ),
));
$handler->override_option('cache', array(
  'type' => 'none',
));
$handler->override_option('title', 'Inhaltsverzeichnis ordnen');
$handler->override_option('empty', 'This book page doesn\'t contain any sub pages.');
$handler->override_option('empty_format', '1');
$handler->override_option('items_per_page', 0);
$handler->override_option('use_pager', '1');
$handler->override_option('style_plugin', 'draggabletable');
$handler->override_option('style_options', array(
  'override' => 1,
  'sticky' => 0,
  'order' => 'asc',
  'columns' => array(
    'title' => 'title',
    'name' => 'name',
    'nid' => 'nid',
    'weight' => 'weight',
    'nid_1' => 'nid_1',
  ),
  'info' => array(
    'title' => array(
      'sortable' => 0,
      'separator' => '',
    ),
    'name' => array(
      'sortable' => 0,
      'separator' => '',
    ),
    'nid' => array(
      'sortable' => 0,
      'separator' => '',
    ),
    'weight' => array(
      'sortable' => 0,
      'separator' => '',
    ),
    'nid_1' => array(
      'sortable' => 0,
      'separator' => '',
    ),
  ),
  'default' => '-1',
  'tabledrag_hierarchy' => array(
    'field' => 'nid_1',
    'handler' => 'book',
  ),
  'tabledrag_order' => array(
    'field' => 'weight',
    'handler' => 'book',
  ),
  'draggableviews_extensions' => array(
    'extension_top' => '3',
    'extension_bottom' => '3',
  ),
  'tabledrag_order_visible' => array(
    'visible' => 0,
  ),
  'tabledrag_hierarchy_visible' => array(
    'visible' => 0,
  ),
  'draggableviews_depth_limit' => '-1',
  'draggableviews_repair' => array(
    'repair' => 'repair',
  ),
  'tabledrag_types_add' => 'Add type',
  'tabledrag_expand' => array(
    'expand_links' => 'expand_links',
    'collapsed' => 0,
    'by_uid' => 0,
  ),
  'tabledrag_lock' => array(
    'lock' => 0,
  ),
  'draggableviews_default_on_top' => '1',
  'draggableviews_button_text' => 'Speichern',
  'draggableviews_arguments' => array(
    'use_args' => 0,
  ),
  'draggableviews_book_radios' => '0',
  'draggableviews_book_argument' => 'p',
  'draggableviews_book_filter' => 'none',
));
$handler = $view->new_display('page', 'Page', 'page_1');
$handler->override_option('path', 'node/%/inhaltsverzeichnis-ordnen');
$handler->override_option('menu', array(
  'type' => 'tab',
  'title' => 'Ordnen',
  'description' => '',
  'weight' => '10',
  'name' => 'primary-links',
));
$handler->override_option('tab_options', array(
  'type' => 'none',
  'title' => '',
  'description' => '',
  'weight' => 0,
  'name' => 'navigation',
));

any clue?