Index: subversion/libsvn_client/externals.c
===================================================================
--- subversion/libsvn_client/externals.c	(revision 1710064)
+++ subversion/libsvn_client/externals.c	(working copy)
@@ -250,10 +250,11 @@
               {
                 /* New external... No problem that we can't remove it */
                 svn_error_clear(err);
-                err = NULL;
               }
+            else if (err)
+              return svn_error_trace(err);
 
-            return svn_error_createf(SVN_ERR_WC_PATH_UNEXPECTED_STATUS, err,
+            return svn_error_createf(SVN_ERR_WC_PATH_UNEXPECTED_STATUS, NULL,
                                      _("The external '%s' defined in %s at '%s' "
                                        "cannot be checked out because '%s' is "
                                        "already a versioned path."),