forgot something,,,
If your device has any device administrators with SD card control, it will prevent install of the MTP driver. Once disabled, the driver will install normally.
Steps:
1) On your phone, go to Security -> Device administration->Device adminstrators
2) Check if there are any app's that has admin privilege, you need to deactivate them to gain MTP access.
Please remember if the applicaiton is like an email or something, then you will lose all data when you revoke admin privilege
Hope this helps!