[Plugin: WordPress Importer] error 404 wp-admin/admin.php?import=wordpress&step=2

i get an error 404 when trying to import a backup og my posts. wp-admin/admin.php?import=wordpress&step=2

it goes to the frontpage of the blog. and gives a 404 page. i am using version 0.6 of the plugin on a multisite.

http://ww.wp.xz.cn/extend/plugins/wordpress-importer/