          if (!collection.sort || !collection.sort.fields)
          {
              singleColumnSort = true;
-             var sort:Sort = new Sort();
+             var sort:ISort = new Sort();
              sort.fields = [];
              
              collection.sort = sort;

            return;

        var view:ICollectionView = ICollectionView(dataProvider);
        var sort:Sort = view.sort;
        if (!sort)
        {
            sortIndex = lastSortIndex = -1;

import mx.collections.ICollectionView;
import mx.collections.IViewCursor;
import mx.collections.ItemResponder;
import mx.collections.ISort;
import mx.collections.ISortField;
import mx.collections.Sort;
import mx.collections.SortField;
import mx.collections.errors.ItemPendingError;
