Call Service Pgm Proc from CL

I am attempting to call a procedure in a service program from a CLLE pgm.
The CLLE pgm source is:
PGM
DCL VAR(&PICK_TYPE) TYPE(*CHAR) LEN(1)
DCL VAR(&CMPA) TYPE(*CHAR) LEN(2) VALUE('09')
DCL VAR(&LOC) TYPE(*CHAR) LEN(4) VALUE('09')
DCL VAR(&AREA) TYPE(*CHAR) LEN(4) VALUE('DRY ')
DCL VAR(&EOJ) TYPE(*CHAR) LEN(1)
CALLPRC PRC(GET_WMS_PICK_TYPE) PARM((&CMPA *BYVAL) +
(&LOC *BYVAL) (&AREA *BYVAL) (&EOJ +
*BYVAL)) RTNVAL(&PICK_TYPE)

The prototype for the procedure is:
D Get_WMS_Pick_Type...
D PR LIKE(##FLAG)
D Company LIKE(##CMPA) CONST
D Location LIKE(##LOC) CONST
D Area LIKE(##BINAREA) CONST
D EOJ_Flag LIKE(##FLAG) CONST
D Options(*NoPass)

When I call the procedure, I get a MCH3601 error in the procedure when I attempt to reference the &EOJ parm.
If I change the CL to use *BYREF for the parms, I get a MCH3601 error when the procedure references the return value &PICK_TYPE.

I must be missing something, but can not think of what.

Thanks,

Jeff Young
Sr. Programmer Analyst
IBM -e(logo) server Certified Systems Exper - iSeries Technical Solutions V5R2
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