i was also having the same issue when i purchased my gnote. i format it several time and updated it to final version 4.0.4. but MTP error was still scratching my head. Finally i got the solution. Keep it in mind that there is no problem with your PC neither with gnote. the main culprit is the APPS which you would have downloaded that prevent gnote to get connected to the PC due to some crappy security reasons. Do this to solve the issue:
1. go to settings>security>device administrators.
2. delete what ever is the device administrator since it is creating problem in your note due to some security reasons.
3. BOOM problem solved.
Now connect your gnote to PC. KIES will detect it and you are done.