svn bug?

X:\>svn --version
svn, version 1.8.8 (r1568071)
   compiled Apr 12 2014, 14:17:25 on x86-microsoft-windows

Copyright (C) 2013 The Apache Software Foundation.
This software consists of contributions made by many people;
see the NOTICE file for more information.
Subversion is open source software, see http://subversion.apache.org/

The following repository access (RA) modules are available:

* ra_svn : Module for accessing a repository using the svn network protocol.
  - with Cyrus SASL authentication
  - handles 'svn' scheme
* ra_local : Module for accessing a repository on local disk.
  - handles 'file' scheme
* ra_serf : Module for accessing a repository via WebDAV protocol using serf.
  - using serf 1.3.4
  - handles 'http' scheme
  - handles 'https' scheme

X:\>mkdir repo

X:\>svnadmin create repo

X:\>svn co file:///x:/repo co1
Checked out revision 0.

X:\>svn co file:///x:/repo co2
Checked out revision 0.

X:\>cd co1

X:\co1>md oldtree\parent\child newtree

X:\co1>copy nul oldtree\parent\child\file
        1 Datei(en) kopiert.

X:\co1>svn add oldtree newtree
A         oldtree
A         oldtree\parent
A         oldtree\parent\child
A         oldtree\parent\child\file
A         newtree

X:\co1>svn ci -m "Preparation"
Adding         newtree
Adding         oldtree
Adding         oldtree\parent
Adding         oldtree\parent\child
Adding         oldtree\parent\child\file
Transmitting file data .
Committed revision 1.

X:\co1>cd \co2

X:\co2>svn up
Updating '.':
A    oldtree
A    oldtree\parent
A    oldtree\parent\child
A    oldtree\parent\child\file
A    newtree
Updated to revision 1.

X:\co2>cd \co1

X:\co1>svn rm oldtree\parent\child
D         oldtree\parent\child
D         oldtree\parent\child\file

X:\co1>svn cp oldtree\parent ..\co2\newtree\parent
A         X:\co2\newtree\parent

X:\>cd \co2

X:\co2>svn ci -m "Will it work?"
Adding         newtree\parent
Deleting       newtree\parent\child
svn: E160016: Commit failed (details follow):
svn: E160016: Path 'parent/child' not present