I am using Rails 3 with dhtmlxGrid. I have created a controller called admin in that we defined 3 functions, such as view,data
Try changing the name of your controller to AdminsController. Rails seems to prefer plural controller names.
Just to add on to what @Paul said. Rails really likes it when you use plural for your controllers but at the end of the day if you can match the name of the file admin_controller.rb and the name on the class AdminController then this should also work okay.
Otherwise the rails convention over configuration methodology dictates the pluralization of the controller names.