Regarding dsmetool: I have found that I get a reboot if I try it on the n900 x-terminal BUT if I ssh in (as root) I can get it to work. I once had problems via ssh but I got it to work after the reboot. Since then, I have been able to use dsmetool via ssh to unload and reload between camera-ui and camera-ui2 at will. What happens if you "dsmetool -k camera-ui" as root and then try to run camera-ui2 from the terminal as user?