This should fix any 500 at notifications-page. Thanks @MrZYX an Chandler

db/migrate/20110507212759_remove_type_null_notifications.rb

@@ -0,0 +1,13 @@
+class RemoveTypeNullNotifications < ActiveRecord::Migration
+  def self.up
+    execute <<SQL
+      DELETE FROM notifications
+      WHERE type IS NULL
+SQL
+  end
+
+  def self.down
+    raise ActiveRecord::IrreversibleMigration.new
+  end
+end
+

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20110421120744) do
+ActiveRecord::Schema.define(:version => 20110507212759) do
 
   create_table "aspect_memberships", :force => true do |t|
     t.integer  "aspect_id",  :null => false