Bluetooth adaptor not working on 10.6.8

I would really appreciate if someone could help me with this. I've been fighting it for a few weeks now, searching all over the internet looking for a solution.

My Mac Pro (details below) does not have built-in bluetooth. A USB bluetooth adaptor (IOGear GBU-421) works when I boot into 10.5, but it doesn't work when I boot into 10.6.8.

I've tried replacing the various bluetooth kext files with the kext files from the 10.5 boot drive.

I've tried upgrading the OS to 10.7.

Still not working.

Any ideas?

Here's a strange artifact:

https://www.dropbox.com/s/peqqd7iaczgie1k/Screen shot 2013-09-01 at 3.47.01 PM.png

...notice how at the top it says "Bluetooth power is off. To use Bluetooth, first you must turn it on." Yet, the box next to "On" is checked (and grayed out).

Also, see this:

https://www.dropbox.com/s/akgragnp0322q61/Screen shot 2013-09-01 at 3.51.13 PM.png

And this:

https://www.dropbox.com/s/akgragnp0322q61/Screen shot 2013-09-01 at 3.51.13 PM.png

SPECS:

Model Name: Mac Pro
Model Identifier: MacPro1,1
Processor Name: Dual-Core Intel Xeon
Processor Speed: 2.66 GHz
Number Of Processors: 2
Total Number Of Cores: 4
L2 Cache (per processor): 4 MB
Memory: 11 GB
Bus Speed: 1.33 GHz
Boot ROM Version: MP11.005C.B08
SMC Version (system): 1.7f10
Serial Number (system): G87060DDUPZ
Hardware UUID: 00000000-0000-1000-8000-0017F206C5DE