MEMBERSHIP2 always got a white page

I com from the direct-support and was talking with "Ashokat" wich told me to create a thread about this problem :
1. I install memberships2 to have a lot of service for my client > ok
2. I create a membership base on the selected format and I name it "invité" > ok
3. i click everywhere and got white page with the message "no right to do this"
Why ???