@Sunlite: Could you post the file "device_drivers_KOBOTOUCHEXTENDED.py.json"? This is in the calibre configuration directory. And the simplest way to get to that is to go to the Miscellaneous page of the preferences and click the "Open calibre configuration directory" button.
Also, looking at the code, deleting this will probably solve the problem, but, you will need to do all the configuration again. You could edit the file, find the line containing "file_copy_dir", and delete it. That should workaround the error.
If that file isn't there, there should be a "device_drivers_KOBOTOUCHEXTENDED.py". If that is the case, I think you actually need to delete the line with "replace_lang" in it.
@jgoguen: This look like it is being triggered by migration from the old version of the config file to the new version in the latest calibre. And, when you removed the "replace_lang" option, the migration isn't handling this properly. I think that all the options in "device_drivers_KOBOTOUCHEXTENDED.py" are off by one after the "replace_lang" option.
And thinking about this, a workaround is to delete the file "device_drivers_KOBOTOUCHEXTENDED.py.json" and then delete the line with "replace_lang" in "device_drivers_KOBOTOUCHEXTENDED.py". That seems to stop the error above.
But, then I get an error caused by the following line in "koboextended_config.py" when saving the configuration:
Code:
del p['replace_lang']