There is no language restrictions/requirements. Your advertisers specifically create ads for your site (which you approve or disapprove). If you (as a site owner) only want to allow Dutch ads, it's completely up to your own policies.
If i choose the ad types. Will they be shown automaticly. I have also the other digitalpoint addon. Not sure how to configurate the two.
Yes... 2 of the ad types are controlled by the addon (email and inline keyword/text)... banner ads showing as being available is dependent on your site having the banner serving JavaScript on your site.