Index: vcpx/dualwd.py
===================================================================
--- vcpx/dualwd.py	(revision 452)
+++ vcpx/dualwd.py	(revision 464)
@@ -37,5 +37,5 @@
 
     This class reimplements the two interfaces, dispatching the right method
-    to the right instance.
+    to the right backend.
     """
 
Index: vcpx/target.py
===================================================================
--- vcpx/target.py	(revision 454)
+++ vcpx/target.py	(revision 465)
@@ -321,6 +321,9 @@
         """
 
-        self._prepareTargetRepository(root, target_repository, target_module)
-        self._prepareWorkingDirectory(root, target_repository, target_module)
+        if target_repository:
+            self._prepareTargetRepository(root, target_repository,
+                                          target_module)
+            self._prepareWorkingDirectory(root, target_repository,
+                                          target_module)
 
     def _prepareTargetRepository(self, root, target_repository, target_module):