Forms :: Capturing Video Webcam Using API?

I want to capture video using webcam through developer 6i. i m using ora_ffi package. my package specs are:

PACKAGE CAM IS
WM_CAP CONSTANT PLS_INTEGER:= 1024; -- EQUALS TO '&H400S'
WM_CAP_DRIVER_CONNECT CONSTANT INTEGER := WM_CAP + 10;
WM_CAP_DRIVER_DISCONNECT CONSTANT INTEGER := WM_CAP + 11;
WM_CAP_EDIT_COPY CONSTANT INTEGER := WM_CAP + 30;
WM_CAP_GET_STATUS CONSTANT INTEGER := WM_CAP + 54;
WM_CAP_DLG_VIDEOFORMATCONSTANT INTEGER:= WM_CAP + 41;

[code]....

package body are:

PACKAGE BODY CAM IS
/* Declare the library and function handles. */
USER_LIB_HANDLE ORA_FFI.LIBHANDLETYPE;
AVCP_LIB_HANDLE ORA_FFI.LIBHANDLETYPE;
FH_SM1 ORA_FFI.FUNCHANDLETYPE;
FH_SM2 ORA_FFI.FUNCHANDLETYPE;
FH_SM3 ORA_FFI.FUNCHANDLETYPE;

[code]....

now i call preview window through 'when-button-pressed' code is as:

DECLARE
IDEVICE INT := 0;
IHEIGHT INT := GET_ITEM_PROPERTY('BLOCK3.IMAGE',HEIGHT);
IWIDTH INT := GET_ITEM_PROPERTY('BLOCK3.IMAGE',WIDTH);
BRETURN BOOLEAN;RS INT;
S CAM.CAPSTATUS;
IMAGE_ID INT;

[code]....

when i run form, i will get "FRM-40734:internal error:PL/SQL error occurred.". i checked form through debugger,it gives me "PDE-PPU007" error on this function BEGIN CLAUSE execution.

FUNCTION CAPCREATECAPTUREWINDOWA(LPSZWINDOWNAME VARCHAR2,DWSTYLE INTEGER,X INTEGER,Y INTEGER,NWIDTH INTEGER,NHEIGHT INTEGER,HWNDPARENT INTEGER,NID INTEGER) RETURN PLS_INTEGER IS
BEGIN
RETURN (FF_CAPCREATECAPTUREWINDOWA(FH_CPW,LPSZWINDOWNAME,DWSTYLE,X,Y,NWIDTH,NHEIGHT,HWNDPARENT,NID));
END CAPCREATECAPTUREWINDOWA;