Why won't my iPhone 3G's bluetooth work with my MacBook Pro?

In order for this to be best troubleshooted, i’m starting from scratch. First, i turn on my iPhone’s bluetooth, making it discoverable. Then, using the top bar on my MacBook Pro, i click the Bluetooth button and select “Set Up Bluetooth Device.” I select the “Mobile Phone” choice. it then searches for my iPhone and successfully finds it. It then pairs with my phone, using the 6-digit conformation code. I leave the “Use device as a network port” button unchecked. (Also, i have tried doing this with this option selected, with the same result.) It then says they have both been connected and i click Quit. At this point, my iPhone says it is not connected to my MacBook Pro. When I tap the dialog box with the name of my MacBook in it, it seems like its trying to connect for a short while, then goes back to looking like it just was. When I open the bluetooth preferences on my laptop, it displays the phone, and indicates that it is not connected. When i have this dialog opened, I tap the same dialog box on my iPhone, and the preferences box on the laptop says the phone is connected for about 1½ seconds, then says it is not connected again.

My iPhone is currently running OS 3.0.0. My MacBook Pro is running OS X Leopard 10.5.8.