Are you using a combination of shared folder permissions and NTFS permissions? Is the shared folder permissions set to default and you're only using NTFS? Your network administrator should be able to identify the problem by viewing all permissions assignments.
I keep getting an access denied message when I try to copy to anyones shared folder on the network. In fact this problem is network wide, its the same on all O/S. Our server is Win 2000 server o/s. Until today we could add files to whomevers shared folder we wanted to. We can copy from the shared folder just not to it. Any suggesstions? We are pretty baffled by this.