Error "Domain Violation Occured"

One of my programs requires an incoming parameter, actually three of them.

I have the parameter names declared as standalones: one with a length of 2 
alpha and the other two as dates with a datfmt of *USA

DDENDDATE         S               D   DATFMT(*USA)
DDSTARTDATE       S               D   DATFMT(*USA)
DALPHPARM         S              2     

I am using an *entry statement as follows:

C     *ENTRY        PLIST                             
C                   PARM                    ALPHPARM  
C                   PARM                    DSTARTDATE
C                   PARM                    DENDDATE  

I have ran this in debug mode, in order to check and make sure that I am 
passing the parms correctly, however when I F11 on the dstartdate and 
denddate parms I get the above error message: "Domain Violation Occured"

Does anyone have any clue what the heck this is about?

Douglas

If you bought, it was hauled by a truck - somewhere, sometime.