Bluetooth Hardware not found...?

Okay, so I have Macbook running 10.5
I have used the built in bluetooth on is several times (file transfers and the like) and I even have a bluetooth mouse that I use for more delicate work. Lately, for some reason, my computer can't even detect the built in hardware for bluetooth. Here is the error message I get. Does anyone know what I can do?

bump

I have the same problem. Around 40% of my boots fail to load up the bluetooth hardware required for my wireless keyboard. I run bluetooth setup assisstant and get the message that no bluetooth hardware is detected. A restart always works, but I really don't want to have to restart 40% of my boots!

Thanks in advance.