nextgen plugin upgrade loop

We installed Nextgen gallery, and have it working on the main site, but when I click on it in a blog, we get

Upgrade NextGEN Gallery

The script detect that you upgrade from a older version. Your database tables for NextGEN Gallery is out-of-date, and must be upgraded before you can continue. If you would like to downgrade later, please make first a complete backup of your database and the images.

The upgrade process may take a while, so please be patient.

Start upgrade now…

clicking then gives

Upgrade NextGEN Gallery

Upgrade sucessful

Continue…

but ‘continue’ just repeats the process

Does anyone know how to fix this? Grateful for any help..