Bitmap.Clone not working.. ( It doesn't get any simpler..)

[TG01]

I cannot clone a bitmap.. the error on the offending line says:

Cannot implicitly convert type 'object' to 'System.Drawing.Bitmap'. An explicit conversion exists (are you missing a cast?)

below is the code where is happens , the last line raises the error.

private Bitmap _backBuffer;
private Bitmap _copyBackBuffer;
protected override void OnPaint(PaintEventArgs e)
{

if (_backBuffer == null)
{
_backBuffer = new Bitmap(this.ClientSize.Width, this.ClientSize.Height);
}
_copyBackBuffer=_backBuffer.Clone();


What am I missing here..?
P.S. Casting and such does not change the error.. :(

[TG01]

Ah I got it..
Accidently I got two conflicting using statements

using System.Drawing;
and
using System.Drawing.Drawing2D;