Fatal error on an image description page: Non-string key given

http://de.wikipedia.org/wiki/Datei:SigmarGabrielKettenReaktion.jpg
http://commons.wikimedia.org/wiki/File:SigmarGabrielKettenReaktion.jpg

Backtrace:

#0 /usr/local/apache/common-local/php-1.17/includes/GlobalFunctions.php(780): MessageCache->get(NULL, true, Object(Language))
#1 /usr/local/apache/common-local/php-1.17/includes/GlobalFunctions.php(901): wfMsgGetKey(NULL, true, Object(Language), false)
#2 /usr/local/apache/common-local/php-1.17/languages/Language.php(513): wfMsgExt(NULL, Array)
#3 /usr/local/apache/common-local/php-1.17/languages/Language.php(525): Language->getMessageFromDB(NULL)
#4 /usr/local/apache/common-local/php-1.17/languages/Language.php(799): Language->getMonthName(false)
#5 /usr/local/apache/common-local/php-1.17/languages/Language.php(1521): Language->sprintfDate('j. F Y', false)
#6 /usr/local/apache/common-local/php-1.17/includes/Exif.php(1020): Language->date('20104 4000000')
#7 /usr/local/apache/common-local/php-1.17/includes/media/Bitmap.php(591): FormatExif->getFormattedData()
#8 /usr/local/apache/common-local/php-1.17/includes/filerepo/File.php(926): BitmapHandler->formatMetadata(Object(ForeignDBFile), 'a:43:{s:4:"Make...')
#9 /usr/local/apache/common-local/php-1.17/includes/ImagePage.php(99): File->formatMetadata()
#10 /usr/local/apache/common-local/php-1.17/includes/Wiki.php(464): ImagePage->view()
#11 /usr/local/apache/common-local/php-1.17/includes/Wiki.php(69): MediaWiki->performAction(Object(OutputPage), Object(ImagePage), Object(Title), Object(User), Object(WebRequest))
#12 /usr/local/apache/common-local/php-1.17/index.php(114): MediaWiki->performRequestForTitle(Object(Title), Object(ImagePage), Object(OutputPage), Object(User), Object(WebRequest))
#13 /usr/local/apache/common-local/live-1.5/index.php(3): require('/usr/local/apac...')
#14 {main}

Version: unspecified
Severity: normal