Outputting field profiles

Hello,

I am using mpb to calculate the field profiles of a W1 supercell, and am 
having difficulty with the output.  To get enough of the dispersion 
diagram, I usually calculate the first 50 or so bands, and I want to 
output E, D, and H for say the last ten bands.

To do this, I put

(run
fix-hfield-phase
(get-efield 40)
(output-efield 40)
)

and do a lot of copy and pasting to cover all of the bands, fields, 
etc.  In return, I get:

init-params must be called before get-dfield!
get-dfield must be called before get-efield-from-dfield!
fields, energy dens., or epsilon must be loaded first.
ERROR: In procedure procedure-property:
ERROR: Wrong type argument in position 1: #<unspecified>


many times over.  If I understand the manual, (run) calls init-params, 
so I'm not sure what to do.

Perhaps I'm misunderstanding the band-func syntax?

Any suggestions would be gratefully appreciated!

Regards
Melanie

----------------------------------
Ms Melanie Ayre
Microphotonics Group
School of Physics and Astronomy
University of St Andrews