hi!
we have the same error.
Error log:
HP Fatal error: Call to a member function get_entity() on a non-object in /srv/www/htdocs/wordpress/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/datamapper/package.module.datamapper.php on line 359, referer: https://localhost/wordpress/wp-admin/admin.php?page=ngg_addgallery
WordPress 4.2.1 with NexgenGallery 2.0.66.37 upload works. NextGenGallery 2.0.71 and above upload not working.
