Importer failed to import posts as format “day and name”

The WordPress .xml import file only contains post data and not any site settings, such as permalinks. It seems to me that this is only an issue of setting the permalinks the same way of your old site.

  • Settings -> Permalinks (/wp-admin/options-permalink.php)
  • select Day and name
  • save changes

If WordPress can’t update the .htaccess file, follow this instructions:
http://codex.wordpress.org/Using_Permalinks#Automatically_updating_.htaccess

[update]

In case it is a server problem:

http://codex.wordpress.org/Using_Permalinks#Permalinks_without_mod_rewrite

http://wpengineer.com/2318/pretty-permalinks-without-mod_rewrite/