Issues to edit a Grid/Form in Master Detail

Hello,

I have a problem with a Grid/Form, I created a Master Detail with a single form and after I added the Grid/Form in the Single Form.

When I add a register in the Grid/Form and I edit the register running only the Grid/Form it works perfect, but when I try to edit the register in Grid/Form running the Master Detail it shows me this error.

Somebody can help me please?

grid error.jpg