Lisa answered your question. Sometimes I like to explain it this way:
Make yourself a Use Year chart for your particular use year month. Every year on your use year anniversary you will receive a new allotment of points. You can bank points from one year to the next, or you can borrow from one year into the preceeding year. For an October UY, your chart looks like this:
Use Year.....Vacation Dates
2005.....Oct 1, 2005 through Sep 30, 2006
2006.....Oct 1, 2006 through Sep 30, 2007
2007.....Oct 1, 2007 through Sep 30, 2008
2008.....Oct 1, 2008 through Sep 30, 2009
and so on.
You banked your 2005 UY points, so they're now in your 2006 Use Year, meaning they can be used only for vacations between Oct 1, 2006 and Sep 30, 2007.
Hope this helps