diff --git a/src/calibre/trac/plugins/download.py b/src/calibre/trac/plugins/download.py
index 4c2b9e1a41..1c2b95c668 100644
--- a/src/calibre/trac/plugins/download.py
+++ b/src/calibre/trac/plugins/download.py
@@ -360,7 +360,7 @@ else:
         if hasattr(tar, 'read'):
             subprocess.check_call(['tar', 'xjf', tar.name, '-C', destdir])
         else:
-            tarfile.open(tar, 'r').extractall(destdir)
+            subprocess.check_call(['tar', 'xjf', tar, '-C', destdir])
     
     def main():
         defdir = '/opt/calibre'