OT: Flash plug in

I (actually I'm trying to help the mother in law) am trying to use a website
which requires logging in and uses Flash.

Its here in case anyone is interested.
http://ave.cvc.cervantes.es/login.asp

I can get it to work fine on my XP machine, the login and password boxes are
in the middle of the screen, but on her Vista machine I am drawing a blank.
Flash is intalled but the boxes don't appear and a pop up alert warns about
permissions.

Is there a problem with Vista and Flash? Is there a tick I can put in a box
somewhere that may help?

TIA for any input.

Rick


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