iMovie download issues

I have 2 different users with seperate Apple IDs both having slightly different issues downloading iMovie.

The first has the cloud and arrow icon and when you click to download it gives you a message saying you have previously purchased this app and it will be downloaded at no additional charge. it then immediately stop.

I have signed out and in itunes, restarted the ipad etc.

the second one is saying the imove (and keynotes, pages etc) costs money.

this ipad was purchased as part of a bulk order only 3 months ago and all the other ipads have got imove etc for free.

please help.