throw CreateException issue PT 8.55

Hello,

I am struggling with an error handling issue  with passing error message string based on some conditions. Here is what my code currently looks like:

import PS_PT:Integration:IRequestHandler;

class XXX_INV implements PS_PT:Integration:IRequestHandler

   method Rate();

   method OnRequest(&MSG As Message) Returns Message;

   method OnRequest1(&MSG As Message) Returns Message;

   method OnRequest2(&MSG As Message) Returns Message;

   method OnError(&MSG As Message) Returns string;

   /* property integer OnErrorHttpResponseCode;

   property string OnErrorContentType;*/

 

 

private

   instance integer &ResponseStatusCode;

   instance string &errorMessage;

end-class;

Method OnRequest

.

.

.

If None(&Tbl) Then

&errorMessage = "The invoice you requested does not exist.";

throw CreateException(0, 0, &errorMessage);