I run it from command line.
It isn't ready yet to replace the stock camera-ui. Please don't
use dsmetool. But I must admit, I don't had any reboots
when I used dsmetool.
First, be sure the stock camera-ui does not run.
dsmetool -k /usr/bin/camera-ui
then you can start my app with
dsmetool -t <where ever you put it>

Btw the stock camera-ui in /usr/bin/camera-ui isn't the real
application, but a link to /usr/bin/maemo-invoker.
When you start /usr/bin/camera-ui maemo-invoker
is started and starts (depending on the name of the link)
an application (/usr/bin/camera-ui.launch).
camer-ui.launch is the real camera-ui "application". It isn't really
an application but a shared library with a "main" function.
maemo-launcher now loads the shared library and calls this
main function.
This is how the maemo application framework tries to reduce
the start up time of the stock applications (modest, mediaplayer ...)

regards
Nicolai