OK, update:
Editing world.cfg line "last import path" did not fix it
uninstalling and reinstalling did not fix it
I noticed during the uninstall I was asked whether I wanted to keep packages... I replied NO, but after the uninstall, the whole directory with my personal settings and packages was still there.
So I moved that directory to another location before reinstalling, which forced the installation to recreate those directories. Upon reinstalling this time, the problem was fixed.
So I went back and looked at the files in the personal folder I had moved. Fatal errors logged in the
eng.log file showed similar information to that which was logged in the file_dialog_history.txt
In retrospect I wonder if clearing out the contents of the file dialog history file would have solved the problem without having to reinstall. Clearly the problem originated in one of the files in my personal folder, because that is the only variable that changed