"ValueError : level must be >= 0" when running a diagram filter

Dear MadGraph experts,

I'm trying to generate events, at interference order, for p p > t t~ j and then decay both the tops in a W boson and a b quark.

Since the decay chain does not support the NP^2==2 tag, I'm trying to use a diagram filter, similar to the first one in https://cp3.irmp.ucl.ac.be/projects/madgraph/wiki/FAQ-General-15 , on the process p p > t t~ > w+ b w- b~ j .

What I get is the following error:

Command "generate p p > t t~ > w+ w- b b~ j --diagram_filter" interrupted with error:
ValueError : level must be >= 0

Can you help me fixing this? My version of MadGraph is 2.8.2.
I paste the debug file here below:

set group_subprocesses Auto
set ignore_six_quark_processes False
set low_mem_multicore_nlo_generation False
set complex_mass_scheme False
set gauge unitary
set loop_optimized_output True
set loop_color_flows False
set max_npoint_for_channel 0
set default_unset_couplings 99
set max_t_for_channel 99
set zerowidth_tchannel True
import model sm
define p = g u c d s u~ c~ d~ s~
define j = g u c d s u~ c~ d~ s~
define l+ = e+ mu+
define l- = e- mu-
define vl = ve vm vt
define vl~ = ve~ vm~ vt~
generate p p > w+ w- b b~ j --diagram_filter
Traceback (most recent call last):
  File "/home/matteo/Scrivania/MG5_aMC_v2_8_2/madgraph/interface/extended_cmd.py", line 1541, in onecmd
    return self.onecmd_orig(line, **opt)
  File "/home/matteo/Scrivania/MG5_aMC_v2_8_2/madgraph/interface/extended_cmd.py", line 1490, in onecmd_orig
    return func(arg, **opt)
  File "/home/matteo/Scrivania/MG5_aMC_v2_8_2/madgraph/interface/master_interface.py", line 278, in do_generate
    return self.cmd.do_generate(self, line, *args, **opts)
  File "/home/matteo/Scrivania/MG5_aMC_v2_8_2/madgraph/interface/madgraph_interface.py", line 4666, in do_generate
    self.do_add(" ".join(args))
  File "/home/matteo/Scrivania/MG5_aMC_v2_8_2/madgraph/interface/master_interface.py", line 229, in do_add
    return self.cmd.do_add(self, line, *args, **opts)
  File "/home/matteo/Scrivania/MG5_aMC_v2_8_2/madgraph/interface/madgraph_interface.py", line 3216, in do_add
    myproc = diagram_generation.MultiProcess(myprocdef,
  File "/home/matteo/Scrivania/MG5_aMC_v2_8_2/madgraph/core/diagram_generation.py", line 1593, in __init__
    self.get('amplitudes')
  File "/home/matteo/Scrivania/MG5_aMC_v2_8_2/madgraph/core/diagram_generation.py", line 1632, in get
    self.generate_multi_amplitudes(process_def,
  File "/home/matteo/Scrivania/MG5_aMC_v2_8_2/madgraph/core/diagram_generation.py", line 1668, in generate_multi_amplitudes
    process_definition.set('orders', MultiProcess.\
  File "/home/matteo/Scrivania/MG5_aMC_v2_8_2/madgraph/core/diagram_generation.py", line 2029, in find_optimal_process_orders
    amplitude.generate_diagrams(diagram_filter=diagram_filter)
  File "/home/matteo/Scrivania/MG5_aMC_v2_8_2/madgraph/core/diagram_generation.py", line 798, in generate_diagrams
    res = self.apply_user_filter(res)
  File "/home/matteo/Scrivania/MG5_aMC_v2_8_2/madgraph/core/diagram_generation.py", line 896, in apply_user_filter
    remove_diag = misc.plugin_import('user_filter',
  File "/home/matteo/Scrivania/MG5_aMC_v2_8_2/madgraph/various/misc.py", line 2005, in plugin_import
    _temp = __import__('PLUGIN.%s' % module, globals(), locals(), fcts, -1)
ValueError: level must be >= 0
                          MadGraph5_aMC@NLO Options
                          ----------------
        complex_mass_scheme : False
    default_unset_couplings : 99
                      gauge : unitary
         group_subprocesses : Auto
  ignore_six_quark_processes : False
           loop_color_flows : False
      loop_optimized_output : True
  low_mem_multicore_nlo_generation : False
     max_npoint_for_channel : 0
          max_t_for_channel : 99
               stdout_level : 20 (user set)
         zerowidth_tchannel : True

                         MadEvent Options
                          ----------------
     automatic_html_opening : True
                    nb_core : None
        notification_center : True
                   run_mode : 2

                      Configuration Options
                      ---------------------
                        OLP : MadLoop
                    amcfast : amcfast-config
                   applgrid : applgrid-config
                auto_update : 7
         cluster_local_path : None
           cluster_nb_retry : 1
              cluster_queue : None (user set)
         cluster_retry_wait : 300
               cluster_size : 100
      cluster_status_update : (600, 30)
          cluster_temp_path : None
               cluster_type : condor
                    collier : ./HEPTools/lib
               cpp_compiler : None
             crash_on_error : False
               delphes_path : ./Delphes
                 eps_viewer : None
        exrootanalysis_path : ./ExRootAnalysis
              f2py_compiler : /home/matteo/anaconda3/bin/f2py3 (user set)
          f2py_compiler_py2 : None
          f2py_compiler_py3 : /home/matteo/anaconda3/bin/f2py3 (user set)
                    fastjet : None (user set)
           fortran_compiler : None
                      golem : None (user set)
                 hepmc_path : None (user set)
                  hwpp_path : None (user set)
                     lhapdf : /home/matteo/Scrivania/MG5_aMC_v2_8_2/HEPTools/lhapdf6_py3/bin/lhapdf-config (user set)
                 lhapdf_py2 : None
                 lhapdf_py3 : /home/matteo/Scrivania/MG5_aMC_v2_8_2/HEPTools/lhapdf6_py3/bin/lhapdf-config (user set)
          madanalysis5_path : None (user set)
           madanalysis_path : ./MadAnalysis
  mg5amc_py8_interface_path : None (user set)
                      ninja : ./HEPTools/lib
        output_dependencies : external
            pythia-pgs_path : ./pythia-pgs
               pythia8_path : None (user set)
                    samurai : None
               syscalc_path : ./SysCalc
                    td_path : ./td
                text_editor : None
                thepeg_path : None (user set)
                    timeout : 60
                web_browser : None