We do apologize that regarding with the error code we can't disclose those file since it was internal by our company. rest assured that we are willing to assist you further if you having issue about the drone tello.
Thanks for your support, @Flydrone . I was beginning to think I was too stupid to search.
So I see only one way to find it out. Everytime I hear about a new Errorcode, I ask the support. And I will gather all codes in a list.