Calling OPM RPG with a datastructure...

I am attempting to call an OPM program from an ILE program but when I do I
get an

MCH0801 - Argument associated with external or internal parameter not passed


and multiple (looks like almost as many as individual parameters)

Pointer not set for location referenced.

Basically I'm calling a prompt program which when called from another OPM
program uses a PLIST containing 25 fields.
I created as datastructure to replace the PLIST
* JBA GL account prompt program parameters
d GL317Ds ds
d Glco00 2a Inz('KF')
d Overlay(GL317Ds)
d P@Actp 2a Inz('05')
d Overlay(GL317Ds : *next)
d P@Psti 1a Inz('*')
d Overlay(GL317Ds : *next)
d P@Memo 1a Inz('*')
d Overlay(GL317Ds : *next)
d P@Lgrt 4a Inz('****')
d Overlay(GL317Ds : *next)
d P@Txns 1a Inz('*')
d Overlay(GL317Ds : *next)
d P@Curn 3a Inz('***')
d Overlay(GL317Ds : *next)
d P@Cbco 2a Inz('**')
d Overlay(GL317Ds : *next)
d P@Lgr 3a Inz('***')
d Overlay(GL317Ds : *next)
d P@Onel 1a Inz('*')
d Overlay(GL317Ds : *next)
d P@Msid 7a Inz('ZPL0030')
d Overlay(GL317Ds : *next)
d P#Msgf 10a Inz('PLMSGF')
d Overlay(GL317Ds : *next)
d P#Accn 12a Inz
d Overlay(GL317Ds : *next)
d Pqactp 2a Inz('06')
d Overlay(GL317Ds : *next)
d Pqpsti 1a Inz('*')
d Overlay(GL317Ds : *next)
d Pqmemo 1a Inz('*')
d Overlay(GL317Ds : *next)
d Pqlgrt 4a Inz('****')
d Overlay(GL317Ds : *next)
d Pqtxns 1a Inz('*')
d Overlay(GL317Ds : *next)
d Pqcurn 3a Inz('***')
d Overlay(GL317Ds : *next)
d Pqcbco 2a Inz('**')
d Overlay(GL317Ds : *next)
d Pqlgr 3a Inz('***')
d Overlay(GL317Ds : *next)
d Pqonel 1a Inz('*')
d Overlay(GL317Ds : *next)
d Pqmsid 7a Inz('ZPL0040')
d Overlay(GL317Ds : *next)
d P@Ftid 7a Inz('ZPL0050')
d Overlay(GL317Ds : *next)
d Pqftid 7a Inz('ZPL0060')
d Overlay(GL317Ds : *next)

I then created the prototype

* JBA GL account prompt program
d GL317 PR Extpgm('GL317')
d parameterDs LikeDs(GL317Ds)

and call the program later in the program

// Call the JBA GL account prompt program
GL317(GL317Ds);

When I actually debugged GL317 only the first and second parameters (in the
*ENTRY) had a value, the rest were
in error.

Can anyone see what I'm doing wrong?

Thanks,

Rob