To Network ops,
I don't know if i misunderstood your statement that says, "which all sources say needs to be copied to the NETLOGON folder on the PDC" and then, "when I go to copy the file, I get an "access is denied" error, that the disk is write-protected or already in use.". No offense, that it seems that you do not have any Administrator Account at all that give you the exact ACCESS DENIED prompt.
You see, In an NT Network, creating a policy is too simple even a janitor can do it, and then you SAVE the file, i repeat, SAVE, not copy it as you said.
Anyways, if you want a few tricks on how to do it, just read on.
Open Policy Editor
Double click the ACCOUNT you want to modify,
Modify the ACCOUNT,
Save the modified account to the NETLOGON FOLDER.
Now, if you cannot even get into the PDC's Netlogon folder, its assumable that you have no administrator account to do this.
jun