I need help... again!

I have the following code which takes an image from a file and converts it to a thumbnail.  I am in the process of modifying the code to take the image from a table (datatype is nvarchar(max), the new way to do things with MS SQL Server 2005).  I think I finally got the code to insert the image correctly.  Now I want to display it in my Windows program.  Here is the code to get the image from the table:
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        private void getImage()
        {

            string imageStream = null;
            SqlDataReader rdr = null;

            SqlCommand cmd = new SqlCommand("SELECT ImageType, BookImage FROM tBooks WHERE BookNbr = '" + tbBookNbr.Text + "'",bookConn);
           
            if (bookConn.State == ConnectionState.Closed)
                bookConn.Open();

            rdr = cmd.ExecuteReader();
            while (rdr.Read())
            {
                imageStream = (string)rdr["BookImage"];
            }

            byte[] bytes = System.Text.Encoding.ASCII.GetBytes(imageStream);
            MemoryStream streem = new MemoryStream(bytes);
           
            //System.IO.FileStream stream = new System.IO.FileStream(@"e:\temp\me.jpg", System.IO.FileMode.Open,
            //    System.IO.FileAccess.Read);  <--  this is what was previously passed to the method; I changed it to above 2 lines

            System.IO.MemoryStream tbstream = CreateThumbNail(streem, "jpg", 102, 109);
           
            Bitmap bmp = new Bitmap(tbstream);
            pbBookImage.Image = bmp;
        }
----------------------------------------------------------------------------------------------------------

Here is the supporting code "CreateThumbNail"...
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        private MemoryStream CreateThumbNail(Stream dataStream, string sFileType, int iHeight, int iWidth)
        {

            EncoderParameters encodeParams = new EncoderParameters();
            long[] quality = new long[1];
            quality[0] = 80;
            EncoderParameter encoderParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
            encodeParams.Param[0] = encoderParam;
            ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders();

            ImageCodecInfo jpegICI = null;
            ImageCodecInfo gifICI = null;
            ImageCodecInfo bmpICI = null;
            ImageCodecInfo pngICI = null;

            for (int x = 0; x < arrayICI.Length; x++)
            {
                if (arrayICI[x].FormatDescription.Equals("JPEG"))
                    jpegICI = arrayICI[x];
                else if (arrayICI[x].FormatDescription.Equals("GIF"))
                    gifICI = arrayICI[x];
                else if (arrayICI[x].FormatDescription.Equals("BMP"))
                    bmpICI = arrayICI[x];
                else if (arrayICI[x].FormatDescription.Equals("PNG"))
                    pngICI = arrayICI[x];
            }


            //Get the image from the  stream.
            System.Drawing.Bitmap image = (Bitmap)System.Drawing.Image.FromStream(dataStream);  <-- ERROR IS HERE!


            //Scale factor to resize the image.
            double sImageWidth = image.Width;
            double sImageHeight = image.Height;
            double scaleFactor = 0;

            if (iWidth / sImageWidth < iHeight / sImageHeight)
                scaleFactor = iWidth / sImageWidth;
            else
                scaleFactor = iHeight / sImageHeight;

            int iNewHeight = Convert.ToInt32(sImageHeight * scaleFactor);
            int iNewWidth = Convert.ToInt32(sImageWidth * scaleFactor);


            //Get the thumbnail for the image.
            System.Drawing.Bitmap thumbNail = new System.Drawing.Bitmap(iNewWidth, iNewHeight);
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(thumbNail);
            g.DrawImage(image, new Rectangle(0, 0, thumbNail.Width, thumbNail.Height), 0, 0, image.Width, image.Height, GraphicsUnit.Pixel);
            image.Dispose();

            MemoryStream ms = new MemoryStream();

            //Save the image corresponding to its Type.
            switch (sFileType)
            {
                case "jpg":
                case "jpeg":
                    thumbNail.Save(ms, jpegICI, encodeParams);
                    break;

                case "bmp":
                    thumbNail.Save(ms, bmpICI, encodeParams);
                    break;

                case "gif":
                    thumbNail.Save(ms, gifICI, encodeParams);
                    break;

                case "png":
                    thumbNail.Save(ms, pngICI, encodeParams);
                    break;

            }
            return ms;

        }
-----------------------------------------------------------------------------------

When running this, I get an error (indicated at ERROR IS HERE) stating the following:  Parameter is not valid.

I don't see the problem... can someone please help me?  AGAIN?  :D