Connecting a laptop on two sites

I have two NT4 domains with DHCP servers on seperate sites with a two way trust relationship. Several users work mainly on Site One, but do work from Site Two occasionally. They use laptops with docking stations, and so hold different profiles for each docking station.
One of my users has stopped being able to log in on Site Two. She cannot connect through the Site Two router to access her Logon Server on Site One.
If I manually assign her an IP address in the scope of the Site One DHCP server she connects with no problems. No other user is affected. The only difference is that she is running Win95, whilst everyone else is running Win2000. The rub is that it used to work. As far as I am aware, nothing has changed on the server side.