BAPI_INSPLOT_SETUSAGEDECISION dumping, why?

Question

Hi All,
I'm using BAPI_INSPLOT_SETUSAGEDECISION to update usage decisions on a number of inspection lots.  Here is my code..
loop at gt_batches.
    clear gv_ud_data.
    gv_number = gv_ud_data = gt_batches-prueflos.
    gv_ud_data-ud_plant = gt_batches-werk.
    gv_ud_data-ud_code  = p_vcode.
    gv_ud_data-ud_code_group = p_vcodeg.
    gv_ud_data-ud_selected_set = p_vaus.
    call function 'BAPI_INSPLOT_SETUSAGEDECISION'
      exporting
        number         = gv_number
        ud_data        = gv_ud_data
      importing
        return         = gv_return.
The first call in the bapi is to FM 'QEVC_PROCESS_AUTO_UD' and this is where it's dumping.  It's not even caught by the exceptions are anything. 
Has anyone had a similar experience before and if so what did you do to reslove it?  Am I missing a something.
If anyone could help, I'd be most grateful,
Thanks,
Liz.

Answer 1

Hi Martin,
Firstly thanks for the response.  I don't get any error mesages, it simply stops executing and reverts back to the input screen.  I've been degugging in se37 and it simply stops and throws back to se37 screen.
I will double check my input parameters but I'm fairly sure they're correct.
Regards,
Liz.