Thread:Extension talk:UploadLocal/Error "An unknown error occurred."

MediaWiki 1.19.1. Latest UploadLocal from git. Trying to upload pdf files larger than about 100Mb and I get this error. Switched on php errors but I don't get any additional help. I have tried various combinations of the following in my LocalSettings.php file: error_reporting(-1); ini_set('display_errors',1); ini_set('post_max_size', '800M'); ini_set('upload_max_filesize', '800M'); $wgUploadSizeWarning = 2147483648; $wgMaxUploadSize = 2147483648; $wgMaxShellMemory = 1073741824; $wgMaxShellFileSize = 1073741824; $wgDebugLogFile="/tmp/debug/log"; Any ideas what I might be doing wrong?