diff --git a/app/models/repository/darcs.rb b/app/models/repository/darcs.rb
index 187e478..9da526d 100644
--- a/app/models/repository/darcs.rb
+++ b/app/models/repository/darcs.rb
@@ -21,7 +21,7 @@ class Repository::Darcs < Repository
   validates_presence_of :url, :log_encoding
 
   def self.human_attribute_name(attribute_key_name, *args)
-    attr_name = attribute_key_name
+    attr_name = attribute_key_name.to_s
     if attr_name == "url"
       attr_name = "path_to_repository"
     end