The Invalid Public Structure error is issued in the following situations:
Public Structure <structure> contains an attribute of record type <type> that is not declared as Public: you have a Record attribute, in a public structure, whose definition is not public.
You must set as public the Entity and/or Structure that belongs to the definition of the Record attribute.
Public Structure <structure> contains an attribute of record type <type> that is a reference: you have a Record attribute, in a public structure, with a definition where the underlying Entity and/or Structure is an eSpace reference. You can only expose elements whose owner is the current eSpace.
You must edit this public structure, select the attribute and use entities and/or structures owned by the current eSpace.
Clicking the symbol will take you directly to the public structure offending property.
Expose a Structure | About Error Messages