User Rank and User Title problems
 

Whenever I click on Manage or Add a user rank in the admin cp, the page returns (HTTP 500 Internal Server Error). What is the problem ? I can access the user title but not the rank.

Thes second problem is whenever i want to add a new user title it returns a database error


Invalid SQL:
INSERT INTO usertitle
(title, minposts)
VALUES
('VIP', 20000);

MySQL Error : Duplicate entry '0' for key 1
Error Number : 1062


Please Help