Return 0 byte[] in c#.net

Hi.. Friends, I have the following method in my c#.net web application code to get bytes of the images

public byte[] pstFile(HttpPostedFile hf)
    {       
        Stream fs = default(Stream);
        byte[] bytes1 = null;
        byte[] postfile = null;
        fs = hf.InputStream;
        BinaryReader a = new BinaryReader(hf.InputStream);
        BinaryReader br1 = new BinaryReader(fs);
        bytes1 = a.ReadBytes(hf.ContentLength);
        postfile = bytes1;
        return postfile;
    }

 
but, the problem is that it return the 0 bytes and while I write the same code in another application it is working fine.
 
So, please tell me where I am wrong.
 
Thanks & regards
Parveen Rathi