Hi,
I keep on getting an 'Error 404 - Page not found' error when trying to create a new 'Preferences set' under 'Computers' / 'View/Edit Preferences sets' / 'Add a new Preference set' just after having enterred a name for the new set and having clicked on the '+'.
Thank you DOGUET I verify what you are experiencing. I'll submit this bug.
In the future if you find any other bugs with the website please feel free to submit the bug here.