Failed to save local policy in WIN XP Professional

[Twilling]

Hi, I'm trying to network 2PCs one is XP other is 2K. I can view shared folders from the XP machine but not the other way around. Instead i get an error message that \\computer is not accessible. Logon failure: the user has not granted the requested logon type at this computer. I would then go on to my local security policy on the XP machine to allow the 2K computer to log on locally. But when i add it to the group of users that have permission i get a second error message saying "Failed to save local policy database". Any ideas anyone