Ubuntu EEG triggers parallel port

Please help

I need to send EEG triggers to BrainVision Recorder using the real parallel port. After following the steps described in the webpage, installing the plug in and give permissions, open sesame shows me an error as follows:

Parallel Port Trigger plug-in has been initialized!

In [1]: Parallel Port Trigger plug-in has been initialized!
Starting experiment as ExperimentProcess-4
openexp._canvas.legacy.init_display(): enabling hardware surface
openexp._canvas.legacy.init_display(): enabling double buffering
openexp._canvas.legacy.init_display(): video mode ok
openexp.sampler._legacy.init_sound(): sampling freq = 48000, buffer size = 1024
openexp.sampler._legacy.init_sound(): mixer already initialized, closing
experiment.run(): experiment started at Mon Nov 13 10:48:57 2017
experiment.run(): disabling garbage collection
no active Parallel port
experiment.end(): enabling garbage collection

Could not access the Parallel Port

item-stack: experiment[prepare].new_parallel_port_trigger_init[prepare]
exception type: NameError
exception message: global name 'show_message' is not defined
time: Mon Nov 13 10:48:57 2017

Traceback:
  File "/home/experiment/.local/share/opensesame_plugins/parallel_port_trigger_init/parallel_port_trigger_init.py", line 132, in prepare
    show_message(self.var.port)
NameError: global name 'show_message' is not defined

Very likely it is a problem with the plug in, because it does not even run the dummy mode

Parallel Port Trigger plug-in has been initialized!

In [1]: Parallel Port Trigger plug-in has been initialized!
Starting experiment as ExperimentProcess-5
openexp._canvas.legacy.init_display(): enabling hardware surface
openexp._canvas.legacy.init_display(): enabling double buffering
openexp._canvas.legacy.init_display(): video mode ok
openexp.sampler._legacy.init_sound(): sampling freq = 48000, buffer size = 1024
openexp.sampler._legacy.init_sound(): mixer already initialized, closing
experiment.run(): experiment started at Mon Nov 13 10:59:23 2017
experiment.run(): disabling garbage collection
no active Parallel port
Dummy mode enabled, prepare phase
experiment.end(): enabling garbage collection

Unexpected error

item-stack: experiment[prepare].new_parallel_port_trigger_send[prepare]
exception type: AttributeError
exception message: pptrigger not found
time: Mon Nov 13 10:59:23 2017

Traceback:
  File "/usr/lib/python2.7/dist-packages/libqtopensesame/misc/process.py", line 150, in run
    exp.run()
  File "/usr/lib/python2.7/dist-packages/libopensesame/experiment.py", line 411, in run
    self.items.execute(self.var.start)
  File "/usr/lib/python2.7/dist-packages/libopensesame/item_store.py", line 90, in execute
    self.prepare(name)
  File "/usr/lib/python2.7/dist-packages/libopensesame/item_store.py", line 122, in prepare
    self[name].prepare()
  File "/usr/lib/python2.7/dist-packages/libopensesame/sequence.py", line 124, in prepare
    self.experiment.items.prepare(_item)
  File "/usr/lib/python2.7/dist-packages/libopensesame/item_store.py", line 122, in prepare
    self[name].prepare()
  File "/home/experiment/.local/share/opensesame_plugins/parallel_port_trigger_send/parallel_port_trigger_send.py", line 90, in prepare
    self.init_var()
  File "/home/experiment/.local/share/opensesame_plugins/parallel_port_trigger_send/parallel_port_trigger_send.py", line 75, in init_var
    self.pptrigger = self.experiment.pptrigger
  File "/usr/lib/python2.7/dist-packages/libopensesame/item.py", line 235, in __getattr__
    raise AttributeError(u'%s not found' % var)
AttributeError: pptrigger not found

Any ideas, possible solutions or alternatives would be highly appreciated.
BTW, running Opensesame 3.1 in Ubuntu 16.04
Thanks in advance!