I have resolved this issue So, I am posting my solution here, May be it will help some one.
Phase 1: Debugging
Step 1:Enable Log
Step 2:login to your admin and try to create or edit roles.Now you will get the error message.
Step 3:Open exception.log file and look for Helper files error exp:
exception 'Exception' with message 'Warning: include(Mage/Missingmeta/Helper/Data.php): failed to open stream: No such file or directory
Step 4: Comment the Module which's helper is mention in exception.log file.And repeat step 1.Now will see the problem has gone.
Phase 2: Solution:
Step 5: Make sure your helper config should be :
If your module has adminhtml.xml and you are using wrong configuration for menu.then it will also cause the problem.Make sure you are adding your menu in right way. You can check here how to add menu in admin.