I'm guessing not many people will have much experience with this camera yet, and even fewer will be installing whatsapp on it, so not sure whether you'll get many answers!
did you receive the message in the play store (i.e. it would not install at all) or in the app itself after install?
If it's the former, you might want to check generic android forums (rather than camera forums) as to what the requirements are and if there is a way to get around them. If it's the latter, exactly what message did you get?
(I was going to ask why you wanted to install a messaging app on a camera... but it occurred to me it might actually be a pretty good way of distributing high quality images quickly - I can see this being quite fun at a party or wedding,for example.)