How do I Query 2 Custom Post Types?

Firstly, do not use query_post(), there almost never is reason to do so – take a look at When to use WP_query(), query_posts() and pre_get_posts.

Secondly, read the documentation about the things you want to achieve, here WP_Query – Type Parameters.

Thirdly, take a close look at what you’re writing/copying there might be a syntax error in it, that’s what you’re telling us is implying.

All that said, the following should do the trick.

Code:

$my_query = new WP_Query( array(
    'post_type' => array( 'artwork', 'portfolio' )
) );