Firmata in combination with Xbee

I don't know if I put this in the correct forum, but this looks like the most appropriate subforum.

I have a lilypad arduino with Standard Firmata on it. I used to communicate with bluetooth between the lilypad and my MacBook Pro. Now I replaced the bluetooth module with an Xbee. On my computer I use an Arduino without the AVR chip connected to another Xbee module.

I configured both the Xbee modules to work with each other, but for some reason I cannot connect to my lilypad arduino.

Does anyone have an idea what the problem could be?

Thanks