diff --git a/categories/models.py b/categories/models.py
index 372b760..bb928ae 100644
--- a/categories/models.py
+++ b/categories/models.py
@@ -54,7 +54,8 @@ class Category(models.Model):
         ancestors = self.get_ancestors()
         return ' > '.join([force_unicode(i.name) for i in ancestors]+[self.name,])
         
-mptt.register(Category, order_insertion_by=['name'])
+try: mptt.register(Category, order_insertion_by=['name'])
+except: pass
 
 if RELATION_MODELS:
     category_relation_limits = reduce(lambda x,y: x|y, RELATIONS)