Security Audit Failures - Domain vs not domain

Our network has two computers that are not joined to the domain. The Security Event Logs of these two PCs show long strings of repeated audit failures for logins from users and PCs all over the facility. I do not see the same thing on any of the domain PCs, nor the domain controller. Has anyone seen something similar? Is there a fix other than joining these computers to the domain?

Server = Windows Server 2003 R2
PC OS = Win XP Pro w/Service Pack 2