Thanks for your help. It turns out it is using the nicename field for generating the urls. I’m not sure how this is updated in the wp-admin area, but I went into the db and changed this value to be something that doesn’t contain spaces (ie the same as my username) and now it works perfectly.
Hey Andrea, I have found this is the problem thanks. Can’t work out how to fix it though.
my username is actually nkrisanski. if you goto http://nathan.krisanski.com/members/nkrisanski/, you can see my profile and everything works, but I cannot work out how to tell buddy press to use the correct username in the urls?