Typically the content on one of the pages is too big to fit on your defined master pages, hence an extra page is created for the overflow. Make sure all objects are within the content area boundries as defined by the master pages. You can turn on Window/Drawing Aids/Show Object Boundaries to get a visual as to the size of each object. If there is anything the is on the page boundry (all sides) then ensure that it is inside of the page.
Thanks for the response. It turned out it was the Pagination settings. I selected all pages (except the first) and set Object | Pagination | Place from
(I selected all) to Following Previous and that fixed it for me.