I created the template and worked on it for over an hour. It worked fine. I published it to the newstand with no problem.
I closed nPrinting console and then opened it again.
With no changes to the the template I now get this error when I try to preview it. This is the 2nd time that this has happened. I am assuming nPrinting is not liking something in the expression that it is referencing. But not sure.