Arnold,
Does your screen shot show the original unstructured document or the structured document produced with the conversion table?
I suspect that the fact that there are multiple paragraphs in a cell in the row preceding the mystery rows is irrelevant.
Note that there are no cells in these rows. My guess is that there are indeed three invisible rows in this table, but that each cell in the row with the multi-paragraph cell straddles all the cells in its column. To confirm, click in one of the cells in the row with the multi-paragraph cell and look at the commands on the Table menu. Does it include Straddle or Unstraddle? If Straddle, then my theory is wrong!. If it shows Unstraddle, select that menu item. The empty rows should now show cells in the Structure View and you should be able to delete them.
--Lynne