Destination Folder Access Denied

I have a new PC with Vista Utimate, I want to copy occasional files from my
old PC running XP and on a home network, but without using 'Easy Transfer'. I
am an Administrator on both PCs and 'Own' the folder on the Vista PC
(therefore with full rights) . When I try to drag and drop from the XP PC
(which I can see and browse via the network) to the new Vista PC I get the
error 'Destination Folder Access Denied.......You need permission to perform
this action'. If I drag and drop files from within the Vista PC to this
folder on the same machine, all works ok.
What more 'Permission' do I need to move files from another PC to the Vista
PC?
I have tried turning off UAC and setting permissions for 'everyone' and
'annonymous users 'to the folder but it still will not let me copy files from
another PC on the network......what am I doing wrong? or is this a bug in
Vista? please help

thanks
bj