Could you please try running xdg-open http://www.ubuntu.com in the command line. xdg-open is the script that is run by Ubuntu One to start your preferred browser.
In case that script cannot open the browser as well more investigation will be required - please run
$ bash -x /usr/bin/xdg-open http://ww.ubuntu.com
and copy-paste the output of that command.
Could you please try running xdg-open http:// www.ubuntu. com in the command line. xdg-open is the script that is run by Ubuntu One to start your preferred browser. ww.ubuntu. com
In case that script cannot open the browser as well more investigation will be required - please run
$ bash -x /usr/bin/xdg-open http://
and copy-paste the output of that command.