Q: Device name different and Find my iPhone isn't working

I have 4 Apple's devices and I subscribed them into "Find my iPhone" service in case I lost one of them. Recently, I purchased an iPod Touch 4th Generation, and I wanted to add one more device into said service. However, not only I couldn't look up my iPod on the service, the name I changed recently (ie. iPod Touch -> my iPod) doesn't appear in the newest name. Similar problem occurred in my laptop recognition device (ie. when you entered your iphone/ipad into usb port of laptop, it'll appear device name as you config on "setting"), whereas I use certain name yet when I connected it to my laptop, it appeared differently. Has anybody experience similar problems?