diff --git a/nova/auth/dbdriver.py b/nova/auth/dbdriver.py
index 813cba36..a429b781 100644
--- a/nova/auth/dbdriver.py
+++ b/nova/auth/dbdriver.py
@@ -81,7 +81,7 @@ class DbDriver(object):
             user_ref = db.user_create(context.get_admin_context(), values)
             return self._db_user_to_auth_user(user_ref)
         except exception.Duplicate, e:
-            raise exception.Duplicate(_('User %s already exists') % name)
+            raise exception.UserExists(user=name)
 
     def _db_user_to_auth_user(self, user_ref):
         return {'id': user_ref['id'],
@@ -128,8 +128,7 @@ class DbDriver(object):
         try:
             project = db.project_create(context.get_admin_context(), values)
         except exception.Duplicate:
-            raise exception.Duplicate(_("Project can't be created because "
-                                        "project %s already exists") % name)
+            raise exception.ProjectExists(project=name)
 
         for member in members:
             db.project_add_member(context.get_admin_context(),
diff --git a/nova/auth/ldapdriver.py b/nova/auth/ldapdriver.py
index 093462b9..3f843285 100644
--- a/nova/auth/ldapdriver.py
+++ b/nova/auth/ldapdriver.py
@@ -171,7 +171,7 @@ class LdapDriver(object):
     def create_user(self, name, access_key, secret_key, is_admin):
         """Create a user"""
         if self.__user_exists(name):
-            raise exception.Duplicate(_("LDAP user %s already exists") % name)
+            raise exception.LDAPUserExists(user=name)
         if FLAGS.ldap_user_modify_only:
             if self.__ldap_user_exists(name):
                 # Retrieve user by name
@@ -225,8 +225,7 @@ class LdapDriver(object):
                        description=None, member_uids=None):
         """Create a project"""
         if self.__project_exists(name):
-            raise exception.Duplicate(_("Project can't be created because "
-                                        "project %s already exists") % name)
+            raise exception.ProjectExists(project=name)
         if not self.__user_exists(manager_uid):
             raise exception.LDAPUserNotFound(user_id=manager_uid)
         manager_dn = self.__uid_to_dn(manager_uid)
@@ -464,8 +463,7 @@ class LdapDriver(object):
                        description, member_uids=None):
         """Create a group"""
         if self.__group_exists(group_dn):
-            raise exception.Duplicate(_("Group can't be created because "
-                                        "group %s already exists") % name)
+            raise exception.LDAPGroupExists(group=name)
         members = []
         if member_uids is not None:
             for member_uid in member_uids:
@@ -500,8 +498,7 @@ class LdapDriver(object):
         if not self.__group_exists(group_dn):
             raise exception.LDAPGroupNotFound(group_id=group_dn)
         if self.__is_in_group(uid, group_dn):
-            raise exception.Duplicate(_("User %(uid)s is already a member of "
-                                        "the group %(group_dn)s") % locals())
+            raise exception.LDAPMembershipExists(uid=uid, group_dn=group_dn)
         attr = [(self.ldap.MOD_ADD, 'member', self.__uid_to_dn(uid))]
         self.conn.modify_s(group_dn, attr)
 
diff --git a/nova/tests/test_virt.py b/nova/tests/test_virt.py
index d99ffce9..498ec701 100644
--- a/nova/tests/test_virt.py
+++ b/nova/tests/test_virt.py
@@ -549,6 +549,43 @@ class LibvirtConnTestCase(test.TestCase):
         db.volume_destroy(self.context, volume_ref['id'])
         db.instance_destroy(self.context, instance_ref['id'])
 
+    def test_spawn_with_network_info(self):
+        # Skip if non-libvirt environment
+        if not self.lazy_load_library_exists():
+            return
+
+        # Preparing mocks
+        def fake_none(self, instance):
+            return
+
+        self.create_fake_libvirt_mock()
+        instance = db.instance_create(self.context, self.test_instance)
+
+        # Start test
+        self.mox.ReplayAll()
+        conn = libvirt_conn.LibvirtConnection(False)
+        conn.firewall_driver.setattr('setup_basic_filtering', fake_none)
+        conn.firewall_driver.setattr('prepare_instance_filter', fake_none)
+
+        network = db.project_get_network(context.get_admin_context(),
+                                         self.project.id)
+        ip_dict = {'ip': self.test_ip,
+                   'netmask': network['netmask'],
+                   'enabled': '1'}
+        mapping = {'label': network['label'],
+                   'gateway': network['gateway'],
+                   'mac': instance['mac_address'],
+                   'dns': [network['dns']],
+                   'ips': [ip_dict]}
+        network_info = [(network, mapping)]
+
+        try:
+            conn.spawn(instance, network_info)
+        except Exception, e:
+            count = (0 <= e.message.find('Unexpected method call'))
+
+        self.assertTrue(count)
+
     def tearDown(self):
         self.manager.delete_project(self.project)
         self.manager.delete_user(self.user)