Why does the XDTO error appear and how to solve it?

Question

1C

Tell me, please, why does this error appear in XDTO packages and how can it be solved?

Answer 1

It looks like you defined a new property somewhere. See code.

Answer 2

You've clearly "messed up" something. In a typical package for Document Management, you can easily add your own properties - my DMInternalDocument already consists of half of the new details.