Octorint unable to create a process on Windows

[ArmanHayots]

Exception in thread Thread-1548:
Traceback (most recent call last):
  File "C:\Program Files\Python38\lib\threading.py", line 932, in _bootstrap_inn
er
    self.run()
  File "C:\Program Files\Python38\lib\threading.py", line 870, in run
    self._target(*self._args, **self._kwargs)
  File "c:\octoprint\venv\lib\site-packages\sarge\__init__.py", line 1205, in ru
n_node
    result = getattr(self, method)(node, input, async_)
  File "c:\octoprint\venv\lib\site-packages\sarge\__init__.py", line 1351, in ru
n_command_node
    node.cmd.run(input=input, async_=async_)
  File "c:\octoprint\venv\lib\site-packages\sarge\__init__.py", line 667, in run

    self.process = p = Popen(self.args, **self.kwargs)
  File "C:\Program Files\Python38\lib\subprocess.py", line 858, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "C:\Program Files\Python38\lib\subprocess.py", line 1311, in _execute_chi
ld
    hp, ht, pid, tid = _winapi.CreateProcess(executable, args,
OSError: [WinError 87] The parameter is incorrect

Windows 7 x64 SP1, Slic3r 1.3.0, path to slic3r-console is correct. It has worked before, but stopped after octoprint update, while CuraEngine-Legacy still works.

What am I doing wrong?