"Add Dashlet" not working???

Hello Everyone,
    I am using SugarCRM 6.5.x CE version. I am trying to add dashlet on my screen and it's not working. I have only two dashlet on screen. Whenever I try to add dashlet, it show 'Loading' and it doesn't do at all after that. Please help me soon on this. I am trying this since two weeks. Thank you.