diff --git a/pandora_client/__init__.py b/pandora_client/__init__.py
index 0eeda85..00a9835 100644
--- a/pandora_client/__init__.py
+++ b/pandora_client/__init__.py
@@ -893,7 +893,7 @@ class API(ox.API):
             uploadUrl = data['uploadUrl']
             if uploadUrl.startswith('/'):
                 u = urlparse(url)
-                uploadUrl = '%s//%s%s' (u.scheme, u.netloc, uploadUrl)
+                uploadUrl = '%s//%s%s' % (u.scheme, u.netloc, uploadUrl)
             f = open(filename)
             fsize = os.stat(filename).st_size
             done = 0