“Rendering of admin template [path to template] failed”

Looks like an error related to the HeadSpace2 plugin, see.
http://urbangiraffe.com/support/topic/rendering-of-admin-template-failed-2
http://urbangiraffe.com/support/topic/rendering-of-admin-template-failed-continued

Perhaps the plugin has template support which you’ve enabled but not created the appropriate file for in the theme? I have no idea, i don’t use the plugin, just thinking out loud..

Hope that helps.

error code: 523