[Error] 'System.AccessViolationException' in OpenTK.dll

  void LoadHandler(object sender, EventArgs e)
        {
 
 
            var vertices = GetVector3();
            if (vertices == null)
            {
 
                this.Close();
            }
            else
            {
                GL.Enable(EnableCap.DepthTest);
 
                vbo_size = vertices.Length;
 
 
                GL.GenBuffers(1, out vbo_id);
                GL.BindBuffer(BufferTarget.ArrayBuffer, vbo_id);
                GL.BufferData(BufferTarget.ArrayBuffer, new IntPtr(vertices.Length * BlittableValueType.StrideOf(vertices)), vertices, BufferUsageHint.StaticDraw);
 
 
                // Generate Array Buffer Id
                GL.GenBuffers(1, out vbo_color_id);
 
                // Bind current context to Array Buffer ID
                GL.BindBuffer(BufferTarget.ArrayBuffer, vbo_color_id);
 
                // Send data to buffer
                GL.BufferData(BufferTarget.ArrayBuffer, new IntPtr(colordata.Length * BlittableValueType.StrideOf(vertices)), colordata, BufferUsageHint.StaticDraw);
 
 
            }
        }