it seems that you your macbook pro is running mavericks but is not supporting it natively (guessing so because "allow bluetooth devices to wake this computer" is greyed out)
you can try to
- on your MacbookPro; in BluetoothSettings, "connect to Network" your already paired iPad.
AT THE SAME TIME
- on your iPad, in the Bluetooth Section of your General Settings, click on your Paired Device , e.g.. Macbook Pro.
you really should try to tap simultaneously; then normally, it connects.
with my iPad, this generally works very well.
with the above Settings that you already installed, e.g. Internet Sharing active via Bluetooth Pan and Bluetooth Pan active,
Your Internet sharing should be succesful;
sometimes certain dongles and OsX'es just don't work very well together.
If you use a ThirdPartyUSB BluetoothAdapter, you might need to deactivate the Internal Bluetooth Adapter.
To to do so, download HardWareIOTools via Apple Developer for your Xcode and use the Bluetooth Explorer Utility. (select "HCI Controller")
if you have certain adapter, you can also use ethernet on your iPad