Using a third party DHCP server for your network configuration requires that special attention be paid to the values issued by such a DHCP server to the client workstations within your network.
Double check that your DHCP server is issuing the correct information to your client workstations! i.e. You must set the DHCP server to assign other computers with the IP address of the LAN card of WinRoute's computer as the default gateway and (optionally) DNS server and, of course, the IP address issued to the client workstation must be in the same subnet as the WinRoute computer.
DOUBLE CHECK (!!!) that the internal network card on the WinRoute computer has assigned a fixed IP address (e.g. 192.168.1.1) and this address is issued by DHCP as the Default Gateway to the rest of the network. The DHCP server may not assign an IP address to the WinRoute host!
Example:
NT server with DHCP is running on 192.168.1.1 while WinRoute is running on 192.168.1.5. The default gateway (and DNS if you would use WinRoute DNS) information issued to workstations will be 192.168.1.5.