Caution in k2 documents

Hi
In the K2 documents I get this warning:
caution
JUser: _load: Could not load the user with 'ID': 690
Something that can not be overcome?

Hi,
it means that user which primarily added content was removed.
If you're still using demo content - it doesn't matter, just add new content with current user.
...and delete all old dummy K2 items.

solution #2:
Create a new user, and in database change his ID to 690