On Debian 11 I get the following error:

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Traceback (most recent call last):
  File "/usr/share/inkscape/extensions/raster2laser_gcode.py", line 37, in <module>
    import png
  File "/usr/share/inkscape/extensions/png.py", line 1885
    except ValueError, e:
                     ^
SyntaxError: invalid syntax
 

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Any help will be appreciated.

Greetings,René.

That doesn't appear to be an "official" Inkscape extension; you should check with the developer. It may be the same as this issue, under discussion here: https://github.com/305engineering/Inkscape/issues/32

Thank you Windell.

I will inform the developer.

Greetings,

René.