使用Codeigniter发布JSON会返回500个错误

I'm having trouble returning data from my controller using an ajax post function. What happens here is the user will input a style number, submit that number to the controller. The controller grabs the value submitted, queries the database and returns the results to the controller then the controller returns an array that I then encode into json. But I keep getting a 500 Internal Server Error???I'm having trouble returning data from my contr