There are several issues that can cause catch-up services not to work. Also with BBC services there are two different methods of using iPlayer dependant on whether she has a TiVO box or one of the older V boxes.
So to start with, which type of box is she using?
Cable customer since 1993. Services: FH TV, Sky Sports & Movies (2xV+), Talk Unlim Telco, VIVID 100, Virgin PAYG Mobile