Support for multilanguage sites, Internationalization (I18N)

[abaer]

Hey guys,

I have a problem with switching the language.
The tags at the end of the url simply seem to get dropped and the developer console in Firefox says there is a 302: temporarily moved error and it simply loads the same page again.

I use /parent/slug/ url-structure and

Code:

<?php echo htmlspecialchars(return_i18n_lang_url('de')); ?>

to get the url to the other language.
Neither this, nor manually entering ?lang=en or ?setlang=en work.

I moved the files from a localhost Apache to a subdirectory on the webserver today. It worked just fine in the localhost implementation. And yes, I did put in the new base url in the admin settings. Or do I need to run the entire setup process again on the webserver and copy my templates over?

Edit: Using /slug_en/ at the end works, but is lost as soon as I load another page..
Edit2: I tried to use the search function with "302 moved" which returned nothing, and honestly I wasn't keen on reading 30 pages, so apologies if this has been asked before. (:

best regards,
Anton

EDIT:

Okay, well, maybe this post was a bit prematurely.
I just ran the setup on a fresh directory/subdomain, copied my template folder and now the language switching seems to work..
Still, what settings might prevent the old instance from working properly?