I'd contact GOG support if I were you. That doesn't sound right at all.

Thanks for the assistance gog. You not only change a download for a game that already worked fine, you made it impossible to configure and or list the problem I have. Because of this, I own a game which WILL not work on any pc with vista. Why would they change it-the game worked on my system.

Have you spoken with GOG support yet? IWD1 and IWD2 should work with XP, Vista, 7 and 8. There shouldn't be anything in the installer that prevents it working with Vista.

Possibly it could be a corrupt file on GOG's server as this has happened very recently with The Witcher and they subsequently got it fixed once they were made aware of it.

You cant actually contact them, support is what you should try and do. I tried to do what they said but it wasnt on there. I think they just fucked up by changing it, the game worked fine until they updated it. I dont know how to get in contact with them as there is nothing on support.

http://www.gog.com/support/contact/technical_issues_with_games/icewind_dale_complete or
http://www.gog.com/support/contact/technical_issues_with_games/icewind_dale_2
won't work for you ? You're not exactly clear on what you tried, not tried, won't work, etc. I always had quick answers to my issues, what did they tell ?

You can contact GOG support.

Firstly, there is the support form. Each game has one and you fill it in with details of your problem. GOG support staff then look into it and should give you an answer (it may take a few days to get a reply though, depending on the nature of the issue - you aren't likely to get answers at weekends or on bank holidays either).
The support form for Icewind Dale is located on the support page. Search for the game on the support page and you get some support articles. At the right of the screen is a section titled "Contact our support team" where there is a link for "I can't find solution for my problem". Here is the IWD1 support form.
http://www.gog.com/support/contact/technical_issues_with_games/icewind_dale_complete

Secondly, you can send a message (forum reply or private message) to a blue text GOG staff member in the forums, but try the support form first as different GOG staff do different things.