C Sharp: error object reference not set to an instance of an object

I'm a beginner in C Sharp, and I'm using the VS community, so I found a web cam program and adapted the code where I want to use it here, but when I click on save image, it appears this error:

  

error object reference not set to an instance of an object

And it does not save, can someone help me? I already changed the path that saves but did not change anything.

Follow the code:

    using System;
    using System.Drawing;
    using System.Windows.Forms;
    using System.Drawing.Imaging;

    namespace WindowsFormsApplication1
    {
        public partial class Form1 : Form
        {
            public DirectX.Capture.Filter Camera;
            public DirectX.Capture.Capture CaptureInfo;
            public DirectX.Capture.Filters CamContainer;
            Image capturaImagem;
            public string caminhoImagemSalva = null;

            public Form1()
            {
                InitializeComponent();
            }

            private void Form1_Load(object sender, EventArgs e)
            {
               CamContainer = new DirectX.Capture.Filters();  
               try
               {
                 int no_of_cam = CamContainer.VideoInputDevices.Count;

                 for (int i = 0; i < no_of_cam; i++ )
                 {
                    try
                    {
                            // Obtém o dispositivo de entrada de video
                            Camera = CamContainer.VideoInputDevices[i];

                            // inicializa e captura o dispostivo
                            CaptureInfo = new DirectX.Capture.Capture(Camera, null);

                            // Define a janela de visualização
                            CaptureInfo.PreviewWindow = this.picWebCam;

                            // Capturando o tratamento do evento
                            CaptureInfo.FrameCaptureComplete += AtualizaImagem;

                            // Captura o frame do dispositivo
                            CaptureInfo.CaptureFrame();

                            // Se o dispositivo foi encontrado sem checar o resto
                            break;
                    }
                    catch (Exception ex) 
                    {
                        throw ex;    
                    }
                }
            }
            catch (Exception ex)
            {                
                MessageBox.Show(this, ex.Message);
            }
         }

            public void AtualizaImagem(PictureBox frame)
            {
                try
                {
                    capturaImagem = frame.Image;
                    this.picImagem.Image = capturaImagem;
                }
                catch (Exception ex)
                {
                    MessageBox.Show("Erro " + ex.Message);
                }
            }

            private void btnCaptura_Click(object sender, EventArgs e)
            {
                try
                {
                    CaptureInfo.CaptureFrame();
                }
                catch (Exception ex)
                {
                    MessageBox.Show("Erro " + ex.Message);
                }
            }

            private void btnSalvar_Click(object sender, EventArgs e)
            {
                try
                {
                    caminhoImagemSalva = @"c:\dados\" + "ImagemWebCam" + DateTime.Now.Day.ToString() + DateTime.Now.Month.ToString() + DateTime.Now.Year.ToString() + DateTime.Now.Millisecond.ToString() + ".jpg";
                    picImagem.Image.Save(caminhoImagemSalva, ImageFormat.Jpeg);
                    MessageBox.Show("Imagem salva com sucesso");
                }
                catch(Exception ex)
                {
                    MessageBox.Show("Erro " + ex.Message);
                }
            }

            private void picWebCam_Click(object sender, EventArgs e)
            {

            }

            private void pictureBox1_Click(object sender, EventArgs e)
            {

            }
        }

}

breakpoint:

<?xml version="1.0" encoding="UTF-8"?>

-<BreakpointCollection xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">


-<Breakpoints>


-<Breakpoint>

<Version>15</Version>

<IsEnabled>1</IsEnabled>

<IsVisible>1</IsVisible>

<IsEmulated>0</IsEmulated>

<IsCondition>0</IsCondition>

<ConditionType>WhenTrue</ConditionType>

<LocationType>SourceLocation</LocationType>


-<TextPosition>

<Version>4</Version>

<FileName>.\CapturaImagemWebCam\Form1.cs</FileName>

<startLine>93</startLine>

<StartColumn>16</StartColumn>

<EndLine>93</EndLine>

<EndColumn>75</EndColumn>

<MarkerId>0</MarkerId>

<IsLineBased>0</IsLineBased>

<IsDocumentPathNotFound>0</IsDocumentPathNotFound>

<ShouldUpdateTextSpan>1</ShouldUpdateTextSpan>


-<Checksum>

<Version>1</Version>

<Algorithm>00000000-0000-0000-0000-000000000000</Algorithm>

<ByteCount>0</ByteCount>

<Bytes/>

</Checksum>

</TextPosition>

<NamedLocationText>WindowsFormsApplication1.Form1.btnSalvar_Click(object sender, EventArgs e)</NamedLocationText>

<NamedLocationLine>6</NamedLocationLine>

<NamedLocationColumn>0</NamedLocationColumn>

<HitCountType>NoHitCount</HitCountType>

<HitCountTarget>1</HitCountTarget>

<Language>3f5162f8-07c6-11d3-9053-00c04fa302a1</Language>

<IsMapped>0</IsMapped>

<BreakpointType>PendingBreakpoint</BreakpointType>


-<AddressLocation>

<Version>0</Version>

<MarkerId>0</MarkerId>

<FunctionLine>0</FunctionLine>

<FunctionColumn>0</FunctionColumn>

<Language>00000000-0000-0000-0000-000000000000</Language>

</AddressLocation>

<DataCount>4</DataCount>

<IsTracepointActive>0</IsTracepointActive>

<IsBreakWhenHit>1</IsBreakWhenHit>

<IsRunMacroWhenHit>0</IsRunMacroWhenHit>

<UseChecksum>1</UseChecksum>

<Labels/>

<RequestRemapped>0</RequestRemapped>

<parentIndex>-1</parentIndex>

</Breakpoint>

</Breakpoints>

</BreakpointCollection>