C++ free error , who can help me plz!

if (bFullCourse) {
        long AreaShopListNum = 0;

        if (piAreaInfo->SPKBN == 0)
            AreaShopListNum = HMDetailNum - 2;
        else
            AreaShopListNum = HMDetailNum - 3;

        AreaShopList_T *piAreaShopList = (AreaShopList_T*)malloc(sizeof(AreaShopList_T) * AreaShopListNum);

        int i = 0;
        HMDetail_T* pHMDetail = pioHMDetail;
        AreaShopList_T *pAreaShopList = piAreaShopList;
        while (i < HMDetailNum) {
            if (strcmp(piBaseInfo->BaseCD, pHMDetail->DlvCD) == 0) {
                i++;
                pHMDetail++;
                continue;
            }
            strcpy_s(pAreaShopList->HonNO, pHMDetail->HonNO);
            strcpy_s(pAreaShopList->ShopCD, pHMDetail->DlvCD);

            i++;
            pHMDetail++;
            pAreaShopList++;
        }

        int ret = TimeRoutingW(piBaseInfo, ShopInfoNum, piShopInfo, 1, piAreaInfo, AreaShopListNum, piAreaShopList,
                                pioHMDetail, pszOutputFile, false, bCvs, bWeekExchange);

        <big>free(piAreaShopList);</big>    // error !! why?

        return ret;
    }
    else { ...