Warning JUser: :_load: Unable to load user

Hi, I have K2 component, when cliking on each of 4 articles i got this reponse:
Warning
JUser: :_load: Unable to load user with ID: 42

I wuold like to remove "Rate this item", "Date: Jun 18, 2012" and "Written by" in the same page
but with no result.

Can you help?
Thanks
By

You can see this problem at this link: www.informaticaxtutti.it/en/item/1-kindl...tivo-di-lettura.html

You need to open your database form phpMyAdmin, open #__users table and change ID of superuser record to 42.

You can google for more instructions that is famous issue