Sharing with XP Professional

I have an XP Professional machine that I recently added to my home network.

I have 4 machines, all on 2000 Pro apart from this new one.

It is a workgroup. All machines appear in 'my network places', but I cannot access the XP machine from any of the 2K boxes. I get a 'You are not granted the requested logon type at this computer.'

Why did I not have this with 2k? How do I fix it? The guest account is enabled.

Help appreciated

 

You must be logging on to the XP PC with a username AND password to be able to access the other PCs even via their guest account.