Reposting this as a "not working" post in the hopes it might trigger someone to notice it. I would be happy to apply this patch myself if I could get access. So far I am having to remember to apply my own patch by hand for the blogs that I am migrating from Posterous back to WordPress.
I encountered an error trying to import more than one item from Posterous.
#3 /home/altern8/workspaces/dflydev-website-wp/wp-content/plugins/posterous-importer/posterous.php(215): add_post_meta(15, 'posterous_9ba0b...', Object(SimpleXMLElement), true)
I fixed this by changing the following:
add_post_meta( $post_id, 'posterous_' . $this->bid . '_post_id', $entry->id, true );
add_post_meta( $post_id, 'posterous_' . $this->bid . '_post_id', (string)$entry->id, true );