I think somehow you have an audio file of that in your folder.

Go to the folder and look for a .wav file with the Same Name as the Demo.

Delete that, either from in Band in a Box or just in Windows.

That's just me thinking out loud.

Actually in the 'mixer' try using the Audio Slider, does that affect the track?

There are some confusing parts to that post to be sure.

John Conley
Musica est vita