[Plugin: NextGEN Gallery] wrong language

Great plugin! But: I’m using it with the default german lang file (nggallery-de_DE.mo and .po in /lang) and it appears always in english. There is always an error message at the NGGallery Overview page: “This translation is not yet updated for Version 1.6.0.”
Can you help me?

http://wordpress.org/extend/plugins/nextgen-gallery/