Disc 2 Problem installing Medieval Total War 2

[Magik]

When I install the game, the 1st disc is fine, then It asks me to insert disc 2. It specifically says:

please insert disk 2 that contains the file main/movies/demo_mtw2_campaign.bik.

It asks me to find the path for this, so I click browse, and choose The Disc 2 which i've inserted. Then I click main, then movies - but here is there is no demo_mtw2 etc etc..
It won't install because of it.

Can you give me any help please?

Thanks in advance.