Retrospect 4.3 install problem reported

Chess Edwards writes: "When I open the new Retrospect Express 4.3 update, I get an error message that says that the 'default location required for this install cannot be found. This install will now quit." Then the updater indeed quits. I am trying to install it on a PowerBook G3 (Lombatrd) running Mac OS 9.0.4." Several other readers have confirmed getting this error. There is also a MacFixIt Forums thread on this matter.