Logon Failure Error

I have a windows 2000 AD domain in Native mode. I have started to get failures from different PCs (Win 2K Pro and XP Pro)when they try to access a certain member server in the domain. They get the following error: “Logon Failure: The target account name is incorrect.” I have not been able to figure out what is causing this. Any help would be appreciated. I have read several articles about this happening on Domain Controllers but this server is only a member server. Thanks in advance.