The Python script process exited with an error message

When this error occurs, you will be prompted with the following error message:

This can occur when a simulation uses a Python script in Automatic mode but the script is not able to run (for example because it crashes, because it cannot compile, etc). In order to fix this error, the Python script has to be fixed so that it can run. The recommended way to do this is 

1) selecting the Python script in Manual mode in Ashes, as illustrated in the image below

2) Opening the Python script in a Python IDE and run it in debug.

This will show where in the script the error occurs and so that it can be fixed.