error 500 is shown instead of activation error with english locale

You need to reproduce the activation error somehow.

How to reproduce:
1. Open JCommune and select English locale
2. Sign up new user
3. Go throught the link from activation mail

Actual result:
Error 500 is shown with root case

see file attached for full text

Expected result:
User is activated or human-readable message is displayed about the reason of activation failure

If the same link is opened in new session the correct message is displayed in russian