TH_DELETE_USER not working in background mode

Hi folks,

I am uploading exchange rates in tcurr table by using bapi bapi_create_multiple.

but if end-user in logged in , then bapi throws an error 'Object requested is currently locked by user '.

to avoid this  i am killing session with the help of fm TH_DELETE_USER.

But this fm is not responding in background.

CALL FUNCTION 'ENQUEUE_READ'

         EXPORTING

           gclient               = sy-mandt

           gname                 = gc_rstable

           guname                = ''

         TABLES

           enq                   = gt_enq

         EXCEPTIONS

           communication_failure = 1

           system_failure        = 2

           OTHERS                = 3.

       IF sy-subrc EQ 0.

* Implement suitable error handling here

       ENDIF.

       SORT gt_enq STABLE BY gname.

       READ TABLE gt_enq INTO gw_enq WITH KEY gname = gc_rstable

                                      garg+0(5)  = 'TCURR' BINARY SEARCH.

       IF sy-subrc EQ 0.

         gv_user = gw_enq-guname.

       ENDIF.

CALL FUNCTION 'TH_DELETE_USER'

       EXPORTING

         user                   = gv_user

         client                 = sy-mandt

         tid                    = -1

*      LOGON_ID               = -1

       EXCEPTIONS

         authority_error        = 1

         OTHERS                 = 2

                .

      IF sy-subrc EQ 0.

*** Implement suitable error handling here

      ENDIF.

please suggest what should i do??

Thanks,

Darshan