Faild install of TWN II quickstart.

A new installation of Joomla 1.7 in an new publick_html mapp.

First step. Install TWN II Quickstart.

result:
Joomla! 1.7 Content Management System
Error on deleting file or folder /libraries/joomla/config.php
Error on deleting file or folder /libraries/joomla/import.php
Error on deleting file or folder /libraries/joomla/version.php

Well, I guess its har to delete files not therr. i library so far is:

factory.php
index.html
methods.php

I have yo domains and the same trubble. What to do? Forget loss of money and read a book?