There is a very easy solution to this problem. All you have to do is turn off the authorisation request in the phone. Once you have paired the phone and the pc, go to the paired devices on the phone. Select the pc and go through the settings to Authorisation Request. Turn it off. It should work fine after that.
If it still doesn't work, you may need to uninstall the Nokia modems. Just use the standard modem drivers that come with your PC bluetooth device.