Ora-0000 error when submitting a concurrent request from a trigger - 11.5.10.2

 Hello,

I am getting following error when submitting a concurrent program from a trigger.

{code}
ORA-20002: ORA-20026: 10322991ORA-0000: normal, successful completion
ORA-06512: at "APPS.NPX_RUN_PICKR", line 63
ORA-04088: error during execution of trigger 'APPS.NPX_RUN_PICKR'
{code}

Though, this indicates normal successful completion, it does not generate any request_id. Nor, it launches the concurrent request.

Below is the trigger code. Any idea why this is happening? Thanks, R

{code}
CREATE OR REPLACE TRIGGER APPS.NPX_RUN_PICKR
AFTER INSERT
ON APPS.NPX_PICK_RELEASE
REFERENCING NEW AS NEW OLD AS OLD
FOR EACH ROW
DECLARE

   p_printer        VARCHAR2 (240);