I seem to having some of the same issue with WIn XP that the OP has.
I can get internet access via NAT however when I try to activate Windows I get the dreaded 32777 error. It is not my clock. The clock on the guest and host agree and I even updated the clock with the net using the windows time utility in the guest system.
I don't know what to do on this topic either because all the help I see on the internet says: it's the clock, fool. But it's not the clock.