Error while starting worflow

Hello everyone

I am trying to start a workflow from my program and for this I have written the following code:

LV_WIID TYPE SWW_WIID,
      ls_input_container TYPE swr_cont,
      lt_input_container TYPE TABLE OF swr_cont,
      lt_message_lines TYPE sapi_msg_lines,
      ls_agents TYPE tswhactor with header line.

ls_agents-OTYPE = 'ZN'.
ls_agents-OBJID = 'Ztest'.
APPEND ls_agents.
ls_input_container-element = 'bus_act'.
ls_input_container-value = 'RFBU'.
APPEND ls_input_container TO lt_input_container .
ls_input_container-element = 'header_txt'.
ls_input_container-value = 'test doc'.
APPEND ls_input_container TO lt_input_container .
ls_input_container-element = 'comp_code'.
ls_input_container-value = '001'.
APPEND ls_input_container TO lt_input_container .
ls_input_container-element = 'doc_date'.
ls_input_container-value = sy-datum.
APPEND ls_input_container TO lt_input_container .
ls_input_container-element = 'pstng_date'.
ls_input_container-value = sy-datum.
APPEND ls_input_container TO lt_input_container .
ls_input_container-element = 'fisc_year'.
ls_input_container-value = '2010'.
APPEND ls_input_container TO lt_input_container .
ls_input_container-element = 'fis_period'.
ls_input_container-value = '00'.
APPEND ls_input_container TO lt_input_container .
ls_input_container-element = 'doc_type'.
ls_input_container-value = 'JE'.
APPEND ls_input_container TO lt_input_container .
ls_input_container-element = 'ref_doc_no'.
ls_input_container-value = 'test 1234'.
APPEND ls_input_container TO lt_input_container .

CALL FUNCTION 'SAP_WAPI_START_WORKFLOW'
  EXPORTING
    TASK                      = 'ZZ10000001'
   USER                      = sy-uname
 IMPORTING
   RETURN_CODE               = L_RETURN_CODE
   WORKITEM_ID               = LV_WIID
 TABLES
   INPUT_CONTAINER           = lt_input_container
   MESSAGE_LINES             = lt_message_lines
   AGENTS                    = ls_agents

if sy-subrc = 0.
  commit work.
endif.

but I am getting workflow id value as '0'... I tried to debug and I am getting this error message: "Import container contains errors (are any obligatory elements missing?)"

Can you please what I am missing.

Thanks,

Rajat

Edited by: rajatg on Jun 11, 2010 2:51 PM