I just posted a helpful serial communication sketch. Try that and see if it works for you.
Some Bee modules might need additional signals or control lines to work properly. That’s why many of the Bee socket’s pins are connected to some digital pins. For example:
Bee CTS –> D19
Bee RTS –> D20
Bee DTR –> D23
Bee RI or Assoc –> A5 (via SJ7)
Check the Bee section on the schematic to see how it’s connected.