Using your Cellphone as a modem through Bluetooth can sum times give you hassle and not connect. The same with 3G Dongles to set up Internet the following must be done.
Install The Bluetooth Dongle/Device, Turn on phone Bluetooth and make sure it is visible on Bluetooth network. Pair phone with device.
Go to network setup and setup dial-up connection, When Asked for name any name will do. The dial number will be " *99***1# " under normal circumstances depends on phone data profile because
the " ***1 " refers to the profile number, Finish setup and try.
If not working it is profile problem then no worries we try something else, a PC always has another way around a problem. We just change the dialing number to " *99# " and then we need to go to device manager. ( right-click My Computer - Properties, (Win XP Hardware Tab - Device Manager) ( Win Vista/7 Left side of properties window - Device manager)). Under modem Category choose Bluetooth modem or 3G modem Whichever One we Need to setup to work. (Right-click - Properties then click on advanced Tab) In The Command box enter the following " cgdcont=1, "IP", "INTERNET" ". the Internet part applies to MTN & vodacom if you have virgin mobile this changes to "VDATA". If you use another service provider i found that mostly "INTERNET" works otherwise consult your service provider.
Your connection should work now if not it can be that you perhaps have some other issue.
Hope this helped, Enjoy!!