I just ran into the same issue as truheart. However, I utilized WP_Query in my loop to call my custom post type. My code is similar to:
$args = array( 'post_type' => 'customposttype' );
$loop = new WP_Query( $args );
while ( $loop->have_posts() ) : $loop->the_post();
In this case, I found the way to reset the post data was to run:
$loop->reset_postdata(); instead of wp_reset_postdata(); (due to the fact I have no global $post object defined).
