I'm getting an error during thumbnail generation. This is the error when viewing the file page:
Fout bij het aanmaken van de miniatuurafbeelding: sh: 1: /bin/bash: Permission denied
Something goes wrong in doTransform in PdfHandler.php, but I don't understand what. I suspect the command line gets mangled somewhere. I've replaced $err = wfShellExecWithStderr( $cmd, $retval ); in that function with exec($cmd, $err, $retval);. This seems be a functional workaround.