I had this error too, it led me on a journey of confusion and annoyance.
I tried to open Pages and was told I had an update, so I clicked on the "Update" button. Then the App Store application started and showed me a page with updates for 5 applications, one of which was Pages. I clicked "Update All" and was told "To update these apps, you need to accept them on the Account page in the App Store."
I had no idea where to find the "Account page", so I started hunting through the menus. I found it in the Store menu labelled "View My Account". I'm wondering why there isn't a button on the dialog to take me directly to this page, why the original message doesn't call it the "View My Account page", why it's hard to find and why it's not just labelled "Account page". Who else's account would it be? And what would selecting it in the menu do, other than showing it?
The displayed page was very much like the updates page but with a heading "You have 5 apps to adopt" and an "Accept" button. I'm wondering in what context I "adopt" an application. And since I apparently bought them, why do I need to "adopt" them, and why the button is labelled "accept". What am I accepting? Why do I need to accept something I've already bought, installed and used many times? I've already clicked on an update button and an update all button, what more do I need to do to indicate that I want to update these applications?
And who thinks up this confusing language? So many questions…
Finally I discover that clicking on my avatar at the bottom of the page also takes me to the account page. Genius, disguising a button like that.
Now I realise why I rarely use the App Store application, it's a minefield of dysfunction.