Regarding script problem..

Bit of a Blender and Python noob but python documentation states that the interpreter will look in the same folder as the main script for the import files so should work. I've tried the script and whilst it gets past the import section the code fails later on. My suggestion is to raise this in the Blender forum in case its implementation of Python does something strange with the import search path under certain circumstances (I couldn't see your post there so apologies if you've already done this).

One other thought was to open the python console in Blender and then use the import function to load the BlenderBotForCarrara file to see if you get a more meaningful error messsage.