wp_insert_post fails within wp-admin

Hello – I have a wordpress problem I am trying to figure out; trying to create a wp-admin script that creates a new wp post…

here is the code:

$my_post = array(
‘post_title’ => ‘My post Gman99’,
‘post_content’ => ‘This is my post.’,
‘post_status’ => ‘draft’,
‘post_author’ => 1,
‘post_category’ => array(8,39)
);

$post_id = wp_insert_post( $my_post );
echo $post_id;

And let me stress that this code works fine if I run it on a “front end” page; i just put the code in short code using “short code exec php” plugin and it creates the post no problem and spits out the post id; but when I try to do the same from within wp-admin it fails? dos anyone have any idea why this would be occurring?

thanks, G