The problem occuring while trying to access a folder on a network of a windows xp pro sp2 station and a windows xp sp2 home station:
\\Pc is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions.
Logon failure: the user has not been granted the requested logon type at this computer.
The solution(apart from having all other parameteres of the network configured correctly):
Download and installWindows Server 2003 Resource Kit Tools from Microsoft
Then open Windows Server 2003 Resource Kit Tools cmd and enter the following commands
net user guest /active:yes
ntrights +r SeNetworkLogonRight -u Guest
ntrights -r SeDenyNetworkLogonRight -u Guest
The first command enables network access for Guest, the two subsequent ones change two different policies to allow network access for Guest.