Jenkins not catching Build errors

[Steve Berg]

I am charged with piloting Jenkins for our development team.  I wrote a 
Hello-World type C# app for initial testing.  It contains a Build error, 
but Jenkins reports a successful build.  Any clues?  (Build error is a 
missing semi-colon after "Second box".  Jenkins is reading the code file 
from Subversion.)
 
namespace TestingJenkins
{
    public partial class MainForm : Form
    {
        public MainForm()
        {
            InitializeComponent();
        }
        private void btn_Exit_Click(object sender, EventArgs e)
        {
            MessageBox.Show("First box");
            MessageBox.Show("Second box")
            if (MessageBox.Show("Are you sure you want to exit the 
program?",
                "Verify Exit", MessageBoxButtons.OKCancel) == 
DialogResult.OK)
            {
                if (MessageBox.Show("Really?",
                    "Second Check", MessageBoxButtons.OKCancel) == 
DialogResult.OK)
                {
                    this.Close();
                }
                else
                {
                    MessageBox.Show("Not exiting - B");
                }
            }
            else
            {
                MessageBox.Show("Not exiting - A");
            }
        }
    }
}