Thanks for your suggestions. Displaying the message first isn't a bad idea, since it would probably help to get more attention from the user and retrieve the option he wants for the corrupted items.

About the invalid Home entry, I don't think it's worth trying something; first, if it's corrupted, the other entries (if present) are generally not accessible because it's the first entry in the file. Second, the other entries contain images or 3D models with no information about their role, place and size in the plan.