Try a bigger Picture. I got an "~" a few times as result when I started with tessnet2. After I used a bigger picture (Textsize should be more than 12) the Programm worked fine.
To enlarge the picture and try different sizes, you can use a trackbar and the following code:
C#
Bitmap originalImage = new Bitmap(imagePath, true);
double needdedHeigth = Convert.ToDouble(trackbar1.Value);
double faktor = needdedHeigth / (double)originalImage.Height;
int newWidth = Convert.ToInt32(faktor * (double)originalImage.Width);
Bitmap ORCImage = new Bitmap(originalImage,newWidth,Convert.ToInt32(needdedHeigth));
Use the "OCRImage' Bitmap in the 'DoOCR()' method