Hello,
I've got the same problem, i tried it on firefox, on safari, this message appear when I want to change adresses or to have different adresses for shipping etc,...
TECHNICAL ERROR: unable to save adresses Details: Error thrown: [object Object] Text status: parsererror
Whan I select to deactivate surcharges (sorry i don't know what is it in english, maybe overrides or overloads ?) then it works, but I'm afraid that if they are always deactivated, it could cause more problems with other features on the site.