Problem with usrp_fft.py

Hi all:

I am new to this group and I am GNU radios to listen to a band of
frequencies and see the spectrum by computing the FFT. The following
command

./usrp_fft.py -R B -f 1e6 >> data_fft_1_2.dat

results in the following error… Should I have some display settings
to avoid this? And why do I get a segmentation fault?

Traceback (most recent call last):
File “./usrp_fft.py”, line 251, in ?
main ()
File “./usrp_fft.py”, line 247, in main
app = stdgui.stdapp(app_flow_graph, “USRP FFT”, nstatus=1)
File
“/usr/local/lib/python2.4/site-packages/gnuradio/wxgui/stdgui.py”,
line 36, in init
wx.App.init (self, redirect=False)
File “/usr/lib/python2.4/site-packages/wx-2.6-gtk2-unicode
/wx/_core.py”, line 7700, in init
self._BootstrapApp()
File
“/usr/lib/python2.4/site-packages/wx-2.6-gtk2-unicode/wx/_core.py”,
line 7352, in _BootstrapApp
return core.PyApp__BootstrapApp(*args, **kwargs)
SystemError: wxEntryStart failed, unable to initialize wxWidgets! (Is
DISPLAY set properly?)
Segmentation fault