This is for the Mitsumi Bluetooth USB dongle.
The software suite you get with this is rubbish, so you go to the Mitsumi site for an update, right? They have the Widcomm suite there which is infinitely superior but guess what? You install it and IT DON'T WORK! The problem is the file btwusb.inf has no mention of mitsumi in it, and therefore will not recognise your dongle once installed.
This is what you have to do
1. Download widcomm bluetooth suite 126.96.36.199 from here
2. Unzip to a folder and throw away the file btwusb.inf
3. Replace it with the one I have provided here
4. Continue to install the software as normal as per their instructions.
The Widcomm suite will now recognise your dongle