2wd.txt doesn’t need to have anything in it, it just has to exist.
Did you follow the FAQ instructions http://discourse.weather-watch.com/t/10889? I think you should set up the new directory, put 2wd.txt there, then install into that directory so when the program starts up it sees 2wd.txt and knows to start up as a clean install.
Another thought, if the old install is still there are you sure you are running the new one?