error on excuting the Tcode.

hi experts,

i have oneZ transaction code , by excuting it is giving teh error like " unable to interpret "E" as a number".

i will give teh discription where exactly getting the error .

i have one function module in this ''V51F_HU_HEADER_UPDATE.

in this function module run timr error shows at the lines.

CONCATENATE 'ES_HEADER-' LS_CHANGED-CHANGED_F INTO FIELDNAME.

ASSIGN (FIELDNAME) TO <F>.

IF SY-SUBRC IS INITIAL.

<F> = LS_CHANGED-F_VALUE.

ENDIF.

couls any one help me in this.