If your signature is ok , here is what i think the call should be but i can't be sure since i don't know your dll procedure signature.
DEFINE VAR ipdwMajor AS INTEGER INITIAL 0 NO-UNDO.
DEFINE VAR ipdwMinor AS INTEGER INITIAL 0 NO-UNDO.
DEFINE VAR cpszValidUntil AS MEMPTR NO-UNDO.
DEFINE VAR...