In PCB the outer rectangle can be coloured by
In Ink XML editor click on silkscreen so that it selects the outer rect in the drawing, hold shift and click on the black square on the bottom left colour bar.
There is some error in the copper layers.
I think you have text in copper, it should be in silk,
Copper is for contacts and holes, Silk is all lines and text.
I removed all the text and unindented the silk and copper to one level behind the top node and deleted all the rest, and no error.
