could not determine operating mode

I have been working on connecting to my xbee network with the Java API. I have set up a test environment with 2 nodes, a coordinator and a router. Both in API mode 2. I have verified the 2 nodes are talking with each other through xctu. When I try to connect to the Coordinator with my PC through a usb cable and xbee extension board I get the error “Could not determine operating mode.” The error code has does not have any information regarding what the issue could be (aside from the obvious) and as far as I can tell the documentation tells me that as long as the xbee is in API mode, the connection will work. Are there other settings I need to change in the configuration for this to work? Please help.

What board is the radio mounted on?
What is providing the message “Could not determine operating mode.”?