diff --git a/oml/item/handlers.py b/oml/item/handlers.py
index 95ba34d..fb5e30e 100644
--- a/oml/item/handlers.py
+++ b/oml/item/handlers.py
@@ -172,8 +172,8 @@ class UploadHandler(tornado.web.RequestHandler):
                     ids.append(id)
                     file = File.get(id)
                     if not file:
-                        prefix_books = os.path.join(os.path.expanduser(prefs['libraryPath']), 'Books/')
-                        prefix_imported = os.path.join(prefix_books, '.import/')
+                        prefix_books = os.path.join(os.path.expanduser(prefs['libraryPath']), 'Books' + os.sep)
+                        prefix_imported = os.path.join(prefix_books, '.import' + os.sep)
                         ox.makedirs(prefix_imported)
                         import_name = os.path.join(prefix_imported, filename)
                         n = 1