diff --git a/.travis.yml b/.travis.yml
index ccfdeacbf..0dc878373 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,8 +6,8 @@ python:
 
 env:
   - DJANGO=https://github.com/django/django/zipball/master
-  - DJANGO=django==1.4.1 --use-mirrors
-  - DJANGO=django==1.3.3 --use-mirrors
+  - DJANGO=django==1.4.3 --use-mirrors
+  - DJANGO=django==1.3.5 --use-mirrors
 
 install:
   - pip install $DJANGO
diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index 75ce1b9f9..da588082c 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -581,7 +581,7 @@ class HyperlinkedRelatedField(RelatedField):
         except:
             pass
 
-        raise ValidationError('Could not resolve URL for field using view name "%s"', view_name)
+        raise ValidationError('Could not resolve URL for field using view name "%s"' % view_name)
 
     def from_native(self, value):
         # Convert URL -> model instance pk
@@ -680,7 +680,7 @@ class HyperlinkedIdentityField(Field):
         except:
             pass
 
-        raise ValidationError('Could not resolve URL for field using view name "%s"', view_name)
+        raise ValidationError('Could not resolve URL for field using view name "%s"' % view_name)
 
 
 ##### Typed Fields #####