Q:

Problems Installing APOPT in Pyomo

I am trying to install the solver "APOPT" in Pyomo by following the guidelines laid out below: 
*Instructions for usage:

Place apopt.py in an appropriate folder in the system path (e.g. Linux, /usr/bin/)
Set appropriate permissions to make the script executable (e.g. chmod 775 apopt.py)
In AMPL, Pyomo, or other NL file write, set solver option to apopt.py
Test installation by running apopt.py -test
*

I essentially copy/paste the apopt.py script from the GitHub Repository into a .py file and have placed it in my project folder that I am working in. I think that the permissions should be okay. However, when I run step 3 at the command line I get the following errors: 
WARNING: Failed to create solver with name 'apopt': Failed to set executable
    for solver asl. File with name=apopt either does not exist or it is not
    executable. To skip this validation, call set_executable with
    validate=False.
And when I try to do Step 4 I get: 
'apopt' is not recognized as an internal or external command,
operable program or batch file.
I am not sure why this is happening though?

A:

It sounds like the APOPT executable is not in your system's PATH. 
From your description, I suspect that the solver's name should be --solver=apopt.py instead of --solver=apopt.

