Failed to install languages on ZyXEL NAS 310

Host name: NAS
Operating system: Linux 2.6.31.8
Apache: Apache/2.2.9 (Unix) mod_ssl/2.2.9 OpenSSL/0.9.8o PHP/5.2.8 mod_wsgi/2.4 Python/2.6.2
PHP: 5.2.8
MySQL: 5.1.30
Server load: 4.52 3 1.75
Graphics toolkit: imagemagick

I am unable to add a language to the Gallery package installed on a ZyXEL 310 NAS.

When I select a language, for example Polish, in the Settings->Languages menu and press the "Updated languages" button I can see an error like this:

Update translations
@todo TRANSLATIONS_FETCH_REQUEST_FAILED HTTP/1.1 301 Moved Permanently

Any idea what to do, in particular w/o opening the backdoor of the NAS?

Regards,
Michał