Related Database 10.2 teething problems

Help needed please. The related database development in 10.2 is opening up whole new worlds of options for me. However, I’m obviously missing something in the subtlety of the setup.
This is my panel:

When I try to apply it, I get the following errors (and the first one appears with several attempts between different databases)

Thanks everyone. Enjoying the video’s Jim

This post is being met by a wall of uncharacteristic silence???
I have some more information - This was a database I was working on on my son’s computer to try to avoid confusing my functioning databases on my own computer. I have now tried to use the relations panel on my computer and it is working fine. Therefore wonder if its related to the OS system on his computer - I’ll post this when I next have a chance. In the meantime if no-one else is having this problem you can probably concentrate on bigger picture issues…

Sorry, I got distracted and missed this. I don’t think it’s related to the computer or OS. From the error message, I would say that there is something in the source subset option. From your screenshot it looks blank, but I think something is there. I would suggest looking at the blueprint, or showing us a screenshot of the blueprint. That should reveal anything hidden.