Problem in Accessing Shared Folders

Hi, I have a Windows 2003 Server running as a domain
contrller. All clients are Windows 2000 Pro with SP4.

There are shares created on the server. Full Control has
been granted to the Users (Domain Users) & Administrators
group. But when accessing from the client, I cannot modify
or delete or create new files in the shares.

I have tried logging in as a domain user as well as a
DOMAIN ADMIN from the clien machines. Yet the message I
get is "Access Denied", when I try to create new
files/folders or modify files within the shares.

I then tried giving full control to the following groups:
Everyone, System, Creator/Owner & Authenticated Users.
Yest the same problem. I have reset all permissions on
child objects and also tried taking ownership. Nothing
works. If I work on the server, then there is no problem.
The problem is only for the clients. They can access,
read, list, traverse the shares. Modification is not
permitted. There are no deny permissions for any group.

I am lost. Can anyone please help me. Thanks in advance.