I had to delete ./includes/xml/product_vbcms.xml to upgrade from 2.0.1 (vB 3.8.6) to 2.1.2 (vB 4.1.5 PL1). As I don't need CMS and Blog, I had uninstalled the addons, but the XML file remained. So it's good to here that this check will be changed.
Regarding German language fles, you can find them here (for 2.1.1):
http://www.vbulletin-germany.com/for...es-Sprachpaket