Despite several attempts at a solution, I still can't change the default applications in Ubuntu 11.10. If I change them in system settings they revert back as soon as I close the dialogue. Next time I open the settings, default applications have reverted back to the standards. If I right click a file and try to choose a default application there I get an error message saying "can't create user application configuration folder" etc etc.
I am logged in as the only user created, so I should have rights to change these settings, shouldn't I?