xbee and serial

Hello everybody
First of all this is my first post here, if it is misplaced please place it in the correct section.

I'm bussy making a scensor system that measures the power of a machine and sends it via an xbee-module (S1) to the receiver (xbee S1 connected to arduino uno which is connected to the computer). The sencing and sending is not with arduino, there we use an other chip which sends 2bytes per cycle.

The problem is situated at the communication between the arduino and pc with the xbee. At the moment i use Processing to write (random test) values from the arduino to a .txt file. This fill will be used to publish the information on a website. But when i use the xbeemodule the processing program cannot read from the arduino using the serial usb connection.

Does someone have an idea on how i can store values in a document from an xbee via arduino uno?

You have an Arduino getting data from a sensor. You have that Arduino sending data to an XBee. You have that XBee transmitting the data over the air. You have another XBee receiving the data, and sending it to another Arduino. You have that Arduino sending data to the PC. You have an application on the PC collecting data from the serial port, and writing it to a file. Nothing gets written to the file, so you somehow have arrived at the conclusion that the problem is reading from the serial port.

I'm trying to follow that chain, and not succeeding.

How are the XBees connected to the Arduinos? How are the XBees configured?