Eror while updating translations: Invalid argument supplied for foreach()

I´ve just installed Gallery 3.0.3 on a fresh Debian Wheezy system /w Apache 2.2.22 and PHP 5.4.0. The inital "white page after setup" error could be resolved with the help of http://www.christopher-kunz.de/archives/276-Upgrade-woes-I-Gallery3-and-PHP-5.4.0.html. When I want to update the translations in settings > languages I run into the following error:

Task Update translations started (task id 16)
exception 'ErrorException' with message 'Invalid argument supplied for foreach()' in /srv/www/gallery.debianforum.de/htdocs/modules/gallery/helpers/gallery_task.php:181
Stack trace:
#0 /srv/www/gallery.debianforum.de/htdocs/modules/gallery/helpers/gallery_task.php(181): gallery_error_Core::error_handler(2, 'Invalid argumen...', '/srv/www/galler...', 181, Array)
#1 [internal function]: gallery_task_Core::update_l10n(Object(Task_Model))
#2 /srv/www/gallery.debianforum.de/htdocs/modules/gallery/helpers/task.php(90): call_user_func_array('gallery_task::u...', Array)
#3 /srv/www/gallery.debianforum.de/htdocs/modules/gallery/controllers/admin_maintenance.php(194): task_Core::run('16')
#4 [internal function]: Admin_Maintenance_Controller->run('16')
#5 /srv/www/gallery.debianforum.de/htdocs/modules/gallery/controllers/admin.php(62): call_user_func_array(Array, Array)
#6 [internal function]: Admin_Controller->__call('maintenance', Array)
#7 /srv/www/gallery.debianforum.de/htdocs/system/core/Kohana.php(331): ReflectionMethod->invokeArgs(Object(Admin_Controller), Array)
#8 [internal function]: Kohana_Core::instance(NULL)
#9 /srv/www/gallery.debianforum.de/htdocs/system/core/Event.php(208): call_user_func_array(Array, Array)
#10 /srv/www/gallery.debianforum.de/htdocs/application/Bootstrap.php(67): Event_Core::run('system.execute')
#11 /srv/www/gallery.debianforum.de/htdocs/index.php(102): require('/srv/www/galler...')
#12 {main}
Invalid argument supplied for foreach()

The apache error.log file does not list any errors. The server is installed atm without any PHP compilers/optimizers like eAccelerator, Zend, ... Disabling safe-mode does not help. The Gallery seems to run without any additional errors so far.