For those interested in changing post processor for Vcarve. I got this instant reply from Vectric
You cannot use " marks in the list of commands as these are used to tell the software that this is where a line begins or ends.
On Page 28 of the Post Processor editing guide this is described in more detail.
For example the line:
M291 P"Have you set work coordinates ?" S3.
is replaced with
"M291 P[34]Have you set work coordinates ?[34] S3."
Thanks Vectric for that.