Arduino FFT library from openmusiclabs hangs


I’m using a ‘Bluetooth XBee - Standalone’ module aboard a ‘Grove - XBee Carrier v1.0’. I’m trying to use the Arduino FFT library from openmusiclabs. It compiles ok, but I’m finding that any write to the fft_input[] array simply causes my code to hang. Does that FFT library not work with the XBee/carrier combination that I’m using? Here is a simplified version of their fft_adc_serial.pde example sketch to demonstrate the problem.

#define LOG_OUT 1 // use the log output function
#define FFT_N 256 // set to 256 point fft

#include <FFT.h> // include the library

void setup() {
Serial.begin(57600); // use the serial port

void loop() {
fft_input[0] = 0; // put real data into even bins
fft_input[1] = 0; // set odd bins to 0