AttributeError: module 'plot_utils' has no attribute 'pxPerInch'

[nahid5566]

Traceback (most recent call last):
File "C:\Program Files\Inkscape\share\inkscape\extensions\fourxidraw.py", line 1431, in
e.run()
File "C:\Program Files\Inkscape\share\inkscape\extensions\inkex\base.py", line 131, in run
self.save_raw(self.effect())
File "C:\Program Files\Inkscape\share\inkscape\extensions\fourxidraw.py", line 336, in effect
self.plotDocument()
File "C:\Program Files\Inkscape\share\inkscape\extensions\fourxidraw.py", line 582, in plotDocument
sx = 1.0 / float(plot_utils.pxPerInch)
AttributeError: module 'plot_utils' has no attribute 'pxPerInch'

how can i fix this error..?