I have a similar problem, I just installed it, and at first i got that users couldn't login, they find that when trying to go to their profiles it said "this profile doesn't exist or is no longer available" after one day this error disspaeared and now profiles work just fin(i guess i fixed it and didn't even know it
i just comment that because it might have something to do with the new error:
new users CAN'T REGISTER!
yuo just fill evrything up, but when you hit the submit button it says that "you must be logged in to view this page" !!!
ho0w am I suppose to log in if i'm not even a site member

Another problem: even if i complete the additional info in my profile, it doesn't appear in it:dry:
My site (it's in spanish)
www.nuevecirculos.com.ar