diff --git a/reviewboard/reviews/forms.py b/reviewboard/reviews/forms.py
--- a/reviewboard/reviews/forms.py
+++ b/reviewboard/reviews/forms.py
@@ -212,7 +212,7 @@ class UploadDiffForm(diffviewer_forms.UploadDiffForm):
     """
     def __init__(self, review_request, form_data=None, *args, **kwargs):
         super(UploadDiffForm, self).__init__(review_request.repository,
-                                             form_data, *args, **kwargs)
+                                             *args, **kwargs)
         self.review_request = review_request
 
         if ('basedir' in self.fields and
diff --git a/reviewboard/reviews/views.py b/reviewboard/reviews/views.py
--- a/reviewboard/reviews/views.py
+++ b/reviewboard/reviews/views.py
@@ -66,7 +66,7 @@ def new_review_request(request,
                     diff_file=request.FILES['diff_path'],
                     parent_diff_file=request.FILES.get('parent_diff_path'))
                 return HttpResponseRedirect(review_request.get_absolute_url())
-            except:
+            except (OwnershipError, ChangeSetError):
                 # XXX - OwnershipError or ChangeSetError?
                 #
                 # We're preventing an exception from being thrown here so that