[xwiki-users] LDAP on xwiki

Hi, I am a new user of xwiki and new to LDAP too. I modified the xwiki.cfg and created a few testing entries in LDAP. Then, I can log in with LDAP users and superroot. But with LDAP users, I always see an error, which is "You are not allowed to view this document or perform this action." I searched for solution for quite a while, and I found some others also suffer from the same issue. The only clue I get is MAYBE I need to import users from LDAP. But the import users from LDAP code from xwiki codebase give me another error. (If you want I can paste the complete error stack trace). So, could anyone advice on what I should do? Thanks a lot