Ok. Here is how it was. I have connected two computers trough LAN twisted pair cables, added some IP addresses and after that, I have just shared the desired folders and everything was ok, but when I tried to move several downloaded files from one shared folder to another, the file can't be moved/deleted alert message appeared..,. Why?
Ok, next time when you try to create some bigger network, than you do the following. Turn on simple file sharing from the Windows Explorer view options menu and select- use simple file sharing (recommended). Than under the sharing option from righ click context menu, tick the passed mark on allw other users to modify content, and the problem is solved.