im running OS 10.3.9 on a 1.8GHz imac G5 and im having the exact same problem.  the client, setup and updater all behave as mentioned above. i downloaded the other (old) updater, which worked, and it updated and it now says that all files are up to date.  when launching the client a blank screen with a title bar saying its planeshift cyrstal blue (0.3.014). this screen stays on for about 10 sec. then , as is the case for all 3 files, it "unexpectedly quit."
maybe ive missed the answer to this somewhere in the forum so i will continue looking untill this receives a reply.  thanks.