You should not change anything in the simple program. Leave it as "XButton1".
Disable the Hook plugin in VC (in Options) and restart VC to be safe.
The program needs to be running on the same machine as VoxCommando.
When the simple program is running, every time you click the XButton1 on your mouse, you should see XButton1 mouse events in the VoxCommando history window.
Do you see those?
If you have commands that are triggered by the XButton mouse click, those should be triggered. Is that working?
If so, you can try to use the simple program to change VoxCommando from On to Standby using the mouse. Hopefully it will continue to work even when you are using processor intensive commands like your DXInput looping commands.