Buongiorno a tutti, ho lo stesso errore anche io, inizialmente ho pensato ad un problema di dipendenze così le ho re-installate. Poi ho pensato ad un problema legato al file del logo e l'ho rimosso. Non riesco a risolvere il problema.
Lascio i log qui sotto:

08:42:59] "GET /seedoo/etichetta/20250000005.pdf HTTP/1.1" 500 -
2025-09-14 08:42:59,862 11525 ERROR protocollo-pb werkzeug: Error on request:
Traceback (most recent call last):
  File "/home/emmecoop_consulting/seedoo/venv/lib/python2.7/site-packages/werkzeug/serving.py", line 177, in run_wsgi
    execute(self.server.app)
  File "/home/emmecoop_consulting/seedoo/venv/lib/python2.7/site-packages/werkzeug/serving.py", line 165, in execute
    application_iter = app(environ, start_response)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/service/server.py", line 294, in app
    return self.app(e, s)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/service/wsgi_server.py", line 216, in application
    return application_unproxied(environ, start_response)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/service/wsgi_server.py", line 202, in application_unproxied
    result = handler(environ, start_response)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/http.py", line 1299, in __call__
    return self.dispatch(environ, start_response)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/http.py", line 1273, in __call__
    return self.app(environ, start_wrapped)
  File "/home/emmecoop_consulting/seedoo/venv/lib/python2.7/site-packages/werkzeug/wsgi.py", line 588, in __call__
    return self.app(environ, start_response)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/http.py", line 1273, in __call__
    return self.app(environ, start_wrapped)
  File "/home/emmecoop_consulting/seedoo/venv/lib/python2.7/site-packages/werkzeug/wsgi.py", line 588, in __call__
    return self.app(environ, start_response)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/http.py", line 1273, in __call__
    return self.app(environ, start_wrapped)
  File "/home/emmecoop_consulting/seedoo/venv/lib/python2.7/site-packages/werkzeug/wsgi.py", line 588, in __call__
    return self.app(environ, start_response)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/http.py", line 1273, in __call__
    return self.app(environ, start_wrapped)
  File "/home/emmecoop_consulting/seedoo/venv/lib/python2.7/site-packages/werkzeug/wsgi.py", line 588, in __call__
    return self.app(environ, start_response)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/http.py", line 1273, in __call__
    return self.app(environ, start_wrapped)
  File "/home/emmecoop_consulting/seedoo/venv/lib/python2.7/site-packages/werkzeug/wsgi.py", line 588, in __call__
    return self.app(environ, start_response)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/http.py", line 1453, in dispatch
    result = ir_http._dispatch()
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/addons/base/ir/ir_http.py", line 175, in _dispatch
    return self._handle_exception(e)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/addons/base/ir/ir_http.py", line 145, in _handle_exception
    return request._handle_exception(exception)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/http.py", line 675, in _handle_exception
    return super(HttpRequest, self)._handle_exception(exception)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/addons/base/ir/ir_http.py", line 171, in _dispatch
    result = request.dispatch()
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/http.py", line 693, in dispatch
    r = self._call_function(**self.params)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/http.py", line 319, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/service/model.py", line 118, in wrapper
    return f(dbname, *args, **kwargs)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/http.py", line 316, in checked_call
    return self.endpoint(*a, **kw)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/http.py", line 812, in __call__
    return self.method(*args, **kw)
  File "/home/emmecoop_consulting/seedoo/OCB/openerp/http.py", line 412, in response_wrap
    response = f(*args, **kw)
  File "/home/emmecoop_consulting/seedoo/seedoo-core/seedoo_protocollo_dematerializzazione/controller/etichetta.py", line 192, in etichetta
    company_logo.paste(company_logo_png, (0, 0), company_logo_png)
  File "/home/emmecoop_consulting/seedoo/venv/lib/python2.7/site-packages/PIL/Image.py", line 1335, in paste
    self.im.paste(im, box, mask.im)
ValueError: bad transparency mask

Stesso errore anche a me. Ho installato tutto correttamente.

puoi rivedere tutti i passi della guida relativi a "Installazione dipendenze di sistema", magari ti sei perso qualcosa.