I'm trying to install Julia from source and It fails (julia-users thread), after Isaiah Norton (Julia develper) checked the issue using the shared terminal feature he suspects the following:
The underlying issue is that uv_exepath  fails, leading to flisp being unable to find where it is running , which leads to the error message you observed.
From some cursory googling, my I guess this is an issue with the PythonAnywhere docker and/or apparmor configuration. Clearly it is possible to run Julia under docker (see JuliaBox), so this will likely need to be resolved by PythonAnywhere.
What do you think guys? We'd really love to have Julia running at PythonAnywhere.