We tried to use the Message.Language Property for selecting different Blockpages.
I set the property to fi (Finnland).
I generated a blockpage with an englisch and finnish content file.
But however I receive only the englisch content file..... The value from message.language seems not to be checked. ( i selected value "message.language" Property in settings for this blocking page.
Bug or feature :-)
did you set this setting for the block action container correctly:
It must be set to "Value of...", otherwise it will try German (browser language) and then fall back to english.
I have not tried if it works... but it should :-)
I tried it out and yes, you need the index file indeed. Otherwise the template will not be used... Generally MWG always loads the index first, the index contains a $CONTENT$ variable where the content of the actual template is inserted. Probably the language is "incomplete" without the index.html. You can simply copy&paste it in the GUI using the template editor.