Hi ,
mostly the problem with fieldcatalog ,please do the following
LS_FCAT-COL_POS = 4.
LS_FCAT-FIELDNAME = 'INV_QTY' .
LS_FCAT-OUTPUTLEN = 13.
LS_FCAT-SCRTEXT_L = 'Inv QTY MT' .
LS_FCAT-DATATYPE = 'QUAN' .
LS_FCAT-REF_FIELD = 'MENGE' .
LS_FCAT-REF_TABLE = 'MSEG' .
LS_FCAT-EDIT = 'X'.
LS_FCAT-TABNAME = 'IT_TAB' .
APPEND LS_FCAT TO PT_FIELDCAT .
CLEAR : LS_FCAT .
i hope this will help you .
Thanks,
Thiru.