171: Invalid @header value
The header
metadata name is declared to turn the automatic integration of a @header.nml file off or to link a header file manually. However, the assigned value is neither off
nor a link in your case.
Solution
Assign the value off
to turn the automatic integration of a @header.nml file off:
@ header: off
Use an arrow before the filepath, if you want to point to a header file manually:
@ header: ->/my/banner.nml