problem in field catalog -help

hi,

i have problem while i try to pass my field catalog internal table to IT_FIELDCAT in REUSE_ALV_HIERSEQ_LIST_DISPLAY .

FORM FIELD_CATALOG .

CLEAR WA_FIELDC.

CALL FUNCTION 'REUSE_ALV_FIELDCATALOG_MERGE'

EXPORTING

I_PROGRAM_NAME = WA_REPID

I_INTERNAL_TABNAME = 'IT_HEAD' "I_INTERNAL_TABNAME

I_STRUCTURE_NAME = 'VBAK' "I_STRUCTURE_NAME

I_CLIENT_NEVER_DISPLAY = 'X'

I_INCLNAME = WA_REPID "I_INCLNAME

• I_BYPASSING_BUFFER = I_BYPASSING_BUFFER

• I_BUFFER_ACTIVE = I_BUFFER_ACTIVE

CHANGING

CT_FIELDCAT = IT_FIELDC

• EXCEPTIONS

• INCONSISTENT_INTERFACE = 1

• PROGRAM_ERROR = 2

.

DELETE IT_FIELDC WHERE FIELDNAME <> 'AUTLF' AND

FIELDNAME <> 'KUNNR' AND

FIELDNAME <> 'VSBED' AND

FIELDNAME <> 'LIFSK' AND

FIELDNAME <> 'AUGRU' AND

FIELDNAME <> 'VBELN' AND

FIELDNAME <> 'BSTKD' AND

FIELDNAME <> 'ZTERM' AND

FIELDNAME <> 'PRSDT' AND

FIELDNAME <> 'INCO1' AND

FIELDNAME <> 'INCO2' .

CALL FUNCTION 'REUSE_ALV_FIELDCATALOG_MERGE'

EXPORTING

I_PROGRAM_NAME = WA_REPID

I_INTERNAL_TABNAME = 'IT_ITEM' "I_INTERNAL_TABNAME

I_STRUCTURE_NAME = 'VBAP' "I_STRUCTURE_NAME

• I_CLIENT_NEVER_DISPLAY = 'X'

• I_INCLNAME = WA_REPID "I_INCLNAME

• I_BYPASSING_BUFFER = I_BYPASSING_BUFFER

• I_BUFFER_ACTIVE = I_BUFFER_ACTIVE

CHANGING

CT_FIELDCAT = IT_FIELDC1

• EXCEPTIONS

• INCONSISTENT_INTERFACE = 1

• PROGRAM_ERROR = 2

.

DELETE IT_FIELDC1 WHERE FIELDNAME <> 'POSNR' AND

FIELDNAME <> 'MATNR' AND

FIELDNAME <> ' WERKS' AND

FIELDNAME <> 'LPRIO' AND

FIELDNAME <> 'KWMENG' AND

FIELDNAME <> 'ABGRU' AND

FIELDNAME <> 'MAKTX' AND

FIELDNAME <> 'VDATU' AND

FIELDNAME <> 'PRSDT' AND

FIELDNAME <> 'VBELN' .

LOOP AT IT_FIELDC1 INTO WA_FIELDC.

APPEND WA_FIELDC TO IT_FIELDC. <----

ENDLOOP.

*want to pass IT_FIELDC to IT_FIELDCAT in REUSE_ALV_HIERSEQ_LIST_DISPLAY ,but getting dump error finally.

ganesh