I created a website for my school with silverstripe 3.0. Now I'm configurating accounts for my colleagues but can't create a new group or role - when I click on the "add" button it comes an "internal server error". When I click on "add user" I can get to the form where I can fill the details, when I click on "save changes" I also get an "internal server error". This seems to work anyway, since when I reload the new user appears and I can log in with the given email and password. For roles and groups I don't get past the add button though.
Anybody has a hint what could be the problem? Would appreciate it!