Unable to update Aperture 3.4.4 to 3.5 through Mac App Store

Hello,

Today I installed Mavericks, and also a 100% legitimite version of Aperture.

I ty to update Aperture to version 3.5, but the Mac App Store refuses. After entering my Apple ID details:

Update Unavailable with This Apple ID. This update is for an app downloaded with a different Apple ID. Sign in with that Apple ID and try again.

What do I have to do to get thi fixed?

Thanks in advance.

Best regards,

Sjoerd