@Help Sorry to hear you're having troubles. Are you using the latest spine-unity 4.1 or 4.2-beta runtime package? A very similar issue has been fixed in the past.
I assume that your problem is that you have selected separator-slots which lead to an empty part which contains no attachments, which led to a null reference exception when trying to access the part's material (which is null) in the past. This has however been fixed already.
