I want to create a table in Word with POI-HWPF (e.g. doc format).
My example code is:
Table table = document.getRange().insertTableBefore((short) 2, 2);
The file linked in this old bug report should give you an idea how to do it.
So in essence: You probably need to add some content (i.e. a paragraph in a cell) so that Word has something to render.