Hi Will,
Thanks for your interest in SEBLOD.
Yes "file" is a valid type.
Can you please update your site with the latest package of Joomla! 2.5.x, which is... 2.5.14
Also be sure to check the path of the /tmp folder: Global Configuration > Server > Path to Templ Folder.
Then, try again.. and let us know.
Regards,
Saba.