No!
The toolbox is a container for system tools, script tools, models and toolsets. It's a binary ArcGIS file, and has nothing to do with the error message from the python interpreter.
What you need to know, is which encoding your python script is stored in, and if that is different from ascii, it should say so in the special coding comment in the script's first line. And you need to know the encoding of all data that you read or write.