Some solutions for this error are:

1. Make sure the file names do not have spaces. For example, change "my great song.wav" to "mygreatsong.wav"

2. Render tracks as split WAV files; .L (left) and .R (right) files separately.

3. Stereo WAV files created by Cakewalk Pro and Cakewalk Sonar have formatting and header information that causes problems on Mackie digital recorders. Try importing WAV files into a different audio application and re-saving it as a WAV or AIFF file. Again separate mono files (left file and right file) are recommended.