Assuming the machine is installed on the LAN correctly, on the machine where the file exists, load My Computer. Right click on the drive the file is on and select 'Sharing and security. Under Network Sharing and Security in the center of the page, the drive that the file is on has to have a share name and be setup for the Network either as either Read Only or to allow others on the network to change files on the drive.
With Windows Explorer, right click on the file and look at Properties and make sure attributes are set to Archive, not Read Only.
If the above is correct, look at the Windows user access as night_angel suggests. If that is OK, disable Norton and try to move the file. If it will move with Norton disabled, the problem is a setup option in Norton.
Answered Aug 16, 2010
Edited Aug 16, 2010