NT DHCP client can’t find XP server

My Dell laptop is logs into an NT domain at work using the pc card. At home I use XP ICS using the other nic in the docking station. This worked fine earlier, now I cannot connect at home. I keep getting an error message saying it can’t find the dhcp server. Assigning a static ip and using dns works fine at home but prevents me from connecting at work. Any suggestions?