HR_INFOTYPE_OPERATION short dump

Question

Hi everyone,
I get a short dump  When I use the HR infotype Opertaion on Infotype 105 then I call the update buffer in sapfp50.
Here is the sample code
            call function 'HR_INFOTYPE_OPERATION'
              exporting
                infty                  = '0105'
                number                 = pernr
                record                 = h0105
                operation              = 'INS'
                dialog_mode            = ld_dialog_mode
                nocommit               = space
              importing
                return                 = return
perform update_buffer(sapfp50m).
commit work.
call function 'HR_PSBUFFER_INITIALIZE'.
The operation is successful, but when I try to update the buffer it crashes:
A new value is to be assigned to the field "<PSHDR>", although this field is     
entirely or partly protected against changes.         
1813   IF T777D-NAMST <> SPACE.                                  "QNOK008925                             
1814     MOVE CPREL TO PSHDR.                                             
1815     MOVE CPREL-SUBTY TO PSHDR-SUBTY.                                 
>>>>>    MOVE PSHDR TO <PSHDR>.                                           
1817   ENDIF.                                                             
Does anyone has any idea about this problem?  As I see the problem is that the T777D structure has a data in it and as a result it tries to move PSHDR into the <PSHDR> field symbol. But why does this table has data in it?  Can someone give me a guide to find the solution for this problem?
Thanks.
N.G

Answer 1

Another thing which can be important:
I update secveral infotypes, then at the end I update the PS buffer:
PERFORM update_0105 USING  '0010' wa_stat-email.
PERFORM update_0105 USING  '0020' wa_stat-tel.
PERFORM update_0105 USING  'CELL' wa_stat-mobil.
PERFORM update_0105 USING  '9010' wa_stat-lst.
    perform update_buffer(sapfp50m).
    commit work.
    call function 'HR_PSBUFFER_INITIALIZE'.