error in CCamera->StartViewFinderDirectL( )

Hi Dear friends,
Can any one tell what is the problem here:

Tect aScreenRect=iAppView->Rect();
aScreenRect.Shrink(10,10);

iCamera->StartViewFinderDirectL(CCoeEnv::Static()->WsSession(),CCoeEnv::Static()->
ScreenDevice(),*iAppView->DrawableWindow(), aScreenRect);---//this line gives error

I get error as:---

'CCamera::StartViewFinderDirectL(RWsSession &, CWsScreenDevice &, RWindowBase &, TRect &, TRect &)' (non-static)

'CCamera::StartViewFinderDirectL(RWsSession &, CWsScreenDevice &, RWindowBase &, TRect &)' (non-static)

function call '[CCamera].StartViewFinderDirectL({lval} RWsSession, CWsScreenDevice *, {lval} RDrawableWindow, {lval} TRect)' does not match