If I understand you correctly, you purchased "Pages for iPad" and you would like to open your documents on your MacBook Pro. And, when you do try to open them on your MacBook Pro it responds with an error.
It sounds like you may not have "Pages for Mac" installed on your MacBook Pro.
Your iPad and your MacBook Pro both have an AppStore but they are different and not compatible from one to the other. In other words, if you buy an app from the AppStore on your iPad, that same app can not be used on the Mac because the iPad and the Mac are two different systems.
To resolve your issue, you just need to purchase "Pages for Mac" (or iWork as a bundle) from the Mac AppStore.
Here is the link to download from the Mac AppStore: https://itunes.apple.com/us/app/pages/id409201541?mt=12
After you've installed "Pages for Mac" you can now view, edit and create new documents from your MacBook Pro.
Hope this helps!