Thanks for the response. I seem to be able to launch Rockpool by going to http:/flotil.la/rockpool.
Running rockpool from Terminal launches the browser, but with a directory listing for the root directory - and doesn't appear to start Rockpool.
Curious.
Don't know enough about Kano OS to go delving as to what might be going wrong. But I had always thought that it was just a repackaging of Rasberian with a more child friendly set of applications.