Nonsense: atheism and theism are positions on belief. Agnosticism and gnosticism are positions on knowledge.
From:
http://freethinker.co.uk/2009/09/25/8419/
An atheist agnostic is someone who does not believe in gods and also thinks that the existence of gods cannot be known. This might mean that they don’t believe in gods because they haven’t seen any evidence that supports their existence.
A theist gnostic is someone who believes in a god/gods and thinks that the existence of gods can be known. This position is usually referred to as just ‘theist‘, since people who believe in gods, usually also think that their existence can be known.
An atheist gnostic is someone who does not believe in gods, and who thinks that we can know that gods do not exist. A fairly unusual position, they might think they have found proof of the non-existence of gods, or might have been persuaded by life experiences.
A theist agnostic is someone who believes in gods, but thinks that they could not know for sure that their god exists. Another fairly unusual position, as people who have faith in gods usually also think that their god can be known to be real.