Unable to save changed via dashboard ($.getJSON does not return anything)

Though there is similar issue #976324: Unable to save changes via the dashboard (PHP 5.3) it has solution for different problem, which I could not reproduce.

Problem of this issue:

1.When the blocks are dragged and dropped, it should be reloaded by DrupalContextBlockEditor.prototype.addBlock declared in context_reaction_block.js:

    // Replace item with loading block.
    var blockLoading = $('<div class="context-block-item context-block-loading"><span class="icon"></span></div>');
    ui.item.addClass('context-block-added');
    ui.item.after(blockLoading);
    ui.sender.append(ui.item);

    $.getJSON(Drupal.settings.contextBlockEditor.path, params, function(data) {
      if (data.status) {
        var newBlock = $(data.block);
        if ($('script', newBlock)) {
          $('script', newBlock).remove();
        }
        blockLoading.fadeOut(function() {
          $(this).replaceWith(newBlock);
          self.initBlocks(newBlock);
          self.updateBlocks();
          Drupal.attachBehaviors();
        });
      }
      else {
        blockLoading.fadeOut(function() { $(this).remove(); });
      }
    });

2. getJSON data is never loaded. Drupal.settings.contextBlockEditor.path is equal to //dashboard.

3. Empty blocks could no be identified when saving in editor_form_submit in context_relation_block.inc.

Looks like Drupal.settings.contextBlockEditor.path is wrong, because it could not load any block.