What's error 300-4?
This is a discussion on ✋ within the New Member Introductions - Site Assistance forums, part of the Apple iPad Discussions category; What's error 300-4?...
This article does not seem to show your error code, but maybe it will be of some use anyway; depending on why you are seeing the code.
iOS: Resolving update and restore alert messages
If you have more information related to what you are doing when getting the error code, I might be able to find more out; or not.