DHCP w/2 Scopes - Cannot Join Domain on One

Good morning (or whenever) all!

I have a single DHCP server w/two scopes set up to handle two locations. The remote sites is accessed via a secure T1 handled by two Cisco routers.

Office 1
Server - 192.168.16.10
Router - 192.168.16.1

---- T1 ----

Router - 192.168.18.1
Workstation - 192.168.18.50
Office 2

The routers are configured correctly to allow communication between the two networks. I can ping the server from the remote location, as well as printers and other workstations. Workstations in Office 1 have no problem joining the domain, but when we try to join the domain from the remote office we are prompted for the ID and password (indicating that we are connecting) but after entering this information an error message is presented:

"The following error occured attempting to join the domain "(domain name here)" : The network path was not found."

Additional Info:

Office 1 Scope:
003 Router - 192.168.16.1
006 DNS Server - 192.168.16.10
044 WINS/NBNS Server - 192.168.16.10
046 WINS/NBT Node - 0x8

Office 2 Scope:
003 Router - 192.168.18.1
006 DNS Server - 192.168.16.10
044 WINS/NBNS Server - 192.168.16.10
046 WINS/NBT Node - 0x8

 

What is your subnet mask?