Why Does This Happen?

This is my site Im new at flash so it aint nothing great
http://keiaston.pwp.blueyonder.co.uk/
now the buttons at the top load movies in to the main stage…this works fine on a couple of pcs i checked it on… but on my girlfriends the buttons do nothing…Its a high spec pc…and I cleaned the catches out…any ideas why they wont work on her pc…it seems that her flash plugin wont loadmovies into a main stage???