Hi again, This error is actually due to the non-GL version of the FFT Sink being imported because the OpenGL Python bindings fail – probably because they’re not installed. To rectify this, run: sudo apt-get install python-opengl You can then re-enable the WX sinks in the flow-graph (the first FFT one is important as it is used to select a signal). Balint PS: The ‘Operation not permitted’ is due to not running as root. As Max suggested, use ‘sudo’. GRC will generate the Python code to run (see the console output below). If you find that file, you can also run that file from the console with ‘sudo’ pre-pended, instead of going through GRC (which should generally not be run as root). From: op25-dev(a)yahoogroups.com [mailto:op25-dev@yahoogroups.com] On Behalf Of md123(a)nycap.rr.com Sent: Friday, 15 February 2013 5:18 PM To: op25-dev(a)yahoogroups.com Subject: [op25-dev] Exception running OP25 I am using using ubuntu 12.10 i am trying to run OP25 (python version 2.7.3), in GNU Radio Companion v3.6.3-35-g4435082f and i get an error. So I run the traceback command in terminal: ~$ python -m trace --count -C . op25_grc.py Here is the output with an error: Imported legacy fsk4 Using Volk machine: ssse3_32 Traceback (most recent call last): File "/usr/lib/python2.7/runpy.py", line 162, in run_module_as_main "_main__", fname, loader, pkg_name) File "/usr/lib/python2.7/runpy.py", line 72, in run_code exec code in run_globals File "/usr/lib/python2.7/trace.py", line 819, in main() File "/usr/lib/python2.7/trace.py", line 807, in main t.runctx(code, globs, globs) File "/usr/lib/python2.7/trace.py", line 513, in runctx exec cmd in globals, locals File "op25_grc.py", line 493, in tb = op25_grc() File "op25_grc.py", line 231, in __init_ self.wxgui_fftsink2_0_0.set_callback(wxgui_fftsink2_0_0_callback) File "/usr/local/lib/python2.7/dist-packages/gnuradio/gr/hier_block2.py", line 54, in getattr return getattr(self._hb, name) AttributeError: 'gr_hier_block2_sptr' object has no attribute 'set_callback' I really really want to get OP25 running but have not been able to figure out what is the solution to this error (AttributeError: 'gr_hier_block2_sptr' object has no attribute 'set_callback') . it'll take me ages to figure out how to debug in python. some threads have said its because gnuradio is an older version but in my case it is not. i am wondering if the question is too amateur or something because nobody is lending assistance. Any help will be so very much appreciated. Thanks.