It is impossible to add a shared folder

[Levlg]

There is a network with 4 computers, all of them under WinXP SP2, the
modem - ADSL Router with 4 ports Switch - SKYMASTER. Windows Firewall is
turned on all computers. It's possible to see shared folders of other
computer from any another one.

But since a moment the opportunity TO ADD a shared folder for ONE (only one)
of the computers was gone. It's possible to mark a folder as shared on this
computer, but it's impossible to see this new shared folder from another
computer. When you try to see ALL shared folders of this computer, the
message "You might not have permission to use this network resource"
appears. But it's possible to see a folder of this computer marked as shared
for a long time ago.

How to get rid of this obstacle?

Thank in advance

Lev

 

[Levlg]

I have found the solution by myself. In Group Policy in
Computer Configuration\Windows Settings\Security Settings\Local
Policies\Security Options

in

Network access: Do not allow anonymous enumeration of SAM accounts and
shares

should be Disable.