I've been doing some mucking around with my Leopard 10.5.2 dev server and came across what I think is a bug (or at least a problem). It seems that if you have a folder on a Mac OS X Server 10.5.2 sharepoint, shared via Samba, and the folder has (certain, common) extended attributes, Vista (and possibly XP) users will get an error when they try to download the folder. The error the Vista user will get is: "Error 0x800700FE: The specified extended attribute name was invalid."
It seems that if you 1) have extended attributes on 2) a directory that 3) has a colon in the attribute's key or value, Vista will produce an error and prohibit downloading. Naturally, this is problematic, because users can't always control how EAs are applied. And just about every EA has a colon with MOSX.