Accord.Video.FFMPEG getting error for long video

Question

I use Accord.Video.FFMPEG to extract images every 10 frames from a video. Total frames for this video is 38194 frames. First run is good, I can save image every 10 frames but after run of about 38185 frames i got null return from this code Bitmap bmpBaseOriginal = vReader.ReadVideoFrame();, if I see in the video there is no problem at the end of video.

I do something like this

using (var vReader = new VideoFileReader())
{
    vReader.Open(files[0]);
    TotalFrame = vReader.FrameCount;
    countin = Convert.ToInt32(TotalFrame / Convert.ToDouble(countAsset));
    Fps = vReader.FrameRate.Value;                                
    int a = 0;
    for (int i = 0; i < vReader.FrameCount; i++)
    {
         if(i < vReader.FrameCount - 1)
         {
              Bitmap bmpBaseOriginal = vReader.ReadVideoFrame();
              if (i%10 == 0)
              {
                  a++;
                  bmpBaseOriginal.Save(string.Format("{0}\\{1}.jpeg", dirVideo.FullName, a), ImageFormat.Jpeg);
              }
              bmpBaseOriginal.Dispose();
         }
         else
         {
              a++;
              Bitmap bmpBaseOriginal = vReader.ReadVideoFrame();
              bmpBaseOriginal.Save(string.Format("{0}\\{1}.jpeg", dirVideo.FullName, a), ImageFormat.Jpeg);
              bmpBaseOriginal.Dispose();
         }
    }
    vReader.Close();
}

this problem occurs again on another video if the video has a lot of frames, but no problem if the video has a less frames.

How to solve it?