Can't change create users, queues, etc

I installed request-tracker-3.8.8 from debian-backports on my Debian
Lenny server with Nginx, Apache and PostgreSQL 9.0.
It works fine, but when I try to create new user or queue, or change
properties of them, I receive an error:
[error]: WebRT: Couldn’t load user ‘’
(/usr/share/request-tracker3.8/html/Elements/Error:82) or Couldn’t
load queue ‘’.
I googled it, but didn’t find anything.
Please help and sorry for my english:)
Alexey Malov