.NET Compact Framework 2.0
Run that MSI, and follow the instructions.
After that has finished, BTAudio Installation is easy.
On your PC:
Download the CAB file to your PC.
Connect your phone to your PC via ActiveSync.
Click "Tools -> Explore Smartphone"
A folder will open in Explorer. Drag the CAB file to that folder.
On your phone:
Start -> File Explorer
Locate the CAB file - it should be in the default folder that File Explorer opens.
Open the CAB - installation will happen automatically.
Back to BTAudio