Getting RuntimeError with demo poisson code

I’m trying to run the script to check my installation is running properly. I installed fenics on WSL using mamba install fenics (see my other post for more details). However, when I run the demo file I get the below error:

Traceback (most recent call last):
  File "/mnt/c/Program Files/JetBrains/PyCharm 2022.3/plugins/python/helpers/pydev/", line 1496, in _exec
    pydev_imports.execfile(file, globals, locals)  # execute the script
  File "/mnt/c/Program Files/JetBrains/PyCharm 2022.3/plugins/python/helpers/pydev/_pydev_imps/", line 18, in execfile
    exec(compile(contents+"\n", file, 'exec'), glob, loc)
  File "/mnt/h/User/Downloads/", line 170, in <module>
    solve(a == L, u, bc)
  File "/home/User/mambaforge/envs/nameofmyenv/lib/python3.9/site-packages/dolfin/fem/", line 220, in solve
    _solve_varproblem(*args, **kwargs)
  File "/home/User/mambaforge/envs/nameofmyenv/lib/python3.9/site-packages/dolfin/fem/", line 241, in _solve_varproblem
    problem = LinearVariationalProblem(eq.lhs, eq.rhs, u, bcs,
  File "/home/User/mambaforge/envs/nameofmyenv/lib/python3.9/site-packages/dolfin/fem/", line 55, in __init__
    L = Form(L, form_compiler_parameters=form_compiler_parameters)
  File "/home/User/mambaforge/envs/nameofmyenv/lib/python3.9/site-packages/dolfin/fem/", line 43, in __init__
    ufc_form = ffc_jit(form, form_compiler_parameters=form_compiler_parameters,
  File "/home/User/mambaforge/envs/nameofmyenv/lib/python3.9/site-packages/dolfin/jit/", line 47, in mpi_jit
    return local_jit(*args, **kwargs)
  File "/home/User/mambaforge/envs/nameofmyenv/lib/python3.9/site-packages/dolfin/jit/", line 95, in ffc_jit
File "/home/User/mambaforge/envs/nameofmyenv/lib/python3.9/site-packages/dolfin/parameter/", line 27, in __getitem__
    raise RuntimeError("Invalid parameter: {}".format(key))
RuntimeError: Invalid parameter: form_compiler

Is this likely due to me installing the package incorrectly? I’m not sure what this form_compiler parameter is.

I would suggest searching the forum for similar posts, see How to fix the RuntimeError "Invalid Parameter" on demo code - #15 by conpierce8