Perdita Durango is rated 'FSK18' in Germany. I believe the German law bans advertising video releases with this rating. I got my DVD from http://www.1a-dvdshop.ch
I have the German 'Perdita Durango' DVD and it does NOT have forced subtitles. In fact, you can also choose English subtitles which comes handy during some sequences spoken in Spanish...
I'd say the German edition is the only one worth getting since all other versions are rather heavily cut...