barcodelib: Insufficient memory error

I’m using the bardcodelib to generate barcodes within PDFs by RDLC-Designer. If many people use our system at the same time, sometimes the PDF will be generated, but the barcode on it is missing and we got following error:

The definition of the report '' is invalid.
InnerException: 
An unexpected error occurred in Report Processing.
InnerException: 
Insufficient memory to continue the execution of the program.

Code snippet:

        public byte[] GetBarCode39(string CodeNumber, int Lenght = 1000, int Height = 200, int FontSize = 40)
        {
            byte[] image = null;

            try
            {
                MemoryStream ms = new MemoryStream();
                Barcode barcode = new Barcode();
                barcode.IncludeLabel = true;
                barcode.Alignment = AlignmentPositions.CENTER;
                barcode.LabelFont = new Font(FontFamily.GenericMonospace, FontSize, FontStyle.Regular);

                var barcodeImage = barcode.Encode(TYPE.CODE39, CodeNumber, System.Drawing.Color.Black, System.Drawing.Color.White, Lenght, Height);

                barcodeImage.Save(ms, ImageFormat.Jpeg);

                image = ms.GetBuffer();
            }
            catch (Exception)
            {
                return null;
            }
            return image;
        }

We already gave more power to the azure webservices, but this didn’t solve the problem… Do you know what’s the problem?