SixBit stores many of its operating parameters such as window locations, settings last used, etc. in a configuration file. There are cases where this file may become corrupted due to power outages, or improper shutdown. This can cause an "Invocation of the constructor" error during startup.
When starting the program, users see an "Invocation of the constructor error as shown here:
This is caused by a corrupt .config file.
Delete the .config file pointed to near the top of the error message (see highlighted area in the image above), then restart SixBit.