POINTER QUESTION: Losing Printer Mappings

Have a small client with a network establised across two sites. Running SBS2003. Have just upgraded PC's from Win2K to Win/XP Pro SP2 and now the Server loses mappings to Printers on the "remote" site PC's if they are logged off.

Network set up is as follows:

Main Office uses 192.168.100.nnn as its IP Range with Server being 192.168.100.1

ISP is providing  a tunnel between the two sites.

Remote Office network is 10.0.0.nnn with the local Router IP being 10.0.0.1

Remote PC's use static IP's and have Gateway set to 10.0.0.1 and DNS/WINS set to 192.168.100.1.

When I set up the PC's and shared the printers I was able to go to the server and map to them. When the remote PC is logged off and on again the Shared Mapping status on the Server stays at "OPENING". If I delete the mapping and try to remap the Server tells me the Printer name is invalid. I can't recover from this unless I reboot the Server and the remote PC's and start again.

I have seen Microsoft KB article Q297684 but it did nothing to help.

Max points for this, it is urgent and causing me great pain.

I have put this question in Networks and Small Business Server topics.