Export Data Issue

I am trying to export a scene from Monet 2.1.4 and I get an error: Couldn’t export clip. Undefined Matte Clip, have you rendered any frames?

What does this mean and how do I fix?
I have tried to pre-render every frame before export.
I have tried to just open a new sequence with no tracking, no insertion and still I get this error. Anyone else have this?