Tascam US-1641 interface and Cakewalk Guitar Studio

Help?
I am new to this forum, and forums in general...
I have Cakewalk Guitar Studio and have been using it succesfully for a few years.
I recently bought an Audio Interface (Tascam US-1641).
It is connected by USB to my Laptop computer with 2 GB of RAM.
I cant seem to get any sound through Cakewalk from my interface.
The interface is receiving, I can see that because the lights on the Interface appear, but there is no output sound coming from cakewalk.
 
Do I have some setting set up wrong?
Could someone guide me through this??? I am so excited about my interface, and cant get it working.
Thanks, Jerry