Null Reference Exception in Button_Click event in Visual Web Part in SharePoint 2010

Hi,

I have created a Visual Web Part suing Visual Studio 2012. The web part contains a button, on click event of the same I validate the input using inline jquery and then if it is valid, then it calls the server side Button_Click event in .ascx.cs file.

When I deploy and run using Visual Studio, web part works fine, but when I create .wsp using TFS build script and deploy, then it throws Null Reference Exception, when I click on the button in my Web Part.

I have put the following code:

namespace MyReportsWebPart
{
    [ToolboxItemAttribute(false)]
    public class ReportsWP : Microsoft.SharePoint.WebPartPages.WebPart
    {
        ReportsWPUserControl control;

        // Visual Studio might automatically update this path when you change the Visual Web Part project item.
        private const string _ascxPath = @"~/_CONTROLTEMPLATES/ReportsWebPart/ReportsWP/ReportsWPUserControl.ascx";

        protected override void CreateChildControls()
        {            
            control = Page.LoadControl(_ascxPath) as ReportsWPUserControl;
            if (control != null)
            {
                control.ReportsWebPart = this;
                Controls.Add(control);
            }
        }

        protected override void OnInit(EventArgs e)
        {
            EnsureChildControls();
            base.OnInit(e);
        }
    }
}

.ascx file:

.ascx.cs file:

namespace MyReportsWebPart
{
    public partial class ReportsWPUserControl : UserControl
    {
        public ReportsWP ReportsWebPart { get; set; }

protected void btnGenerateReport_Click(object sender, EventArgs e)

{

//Some code

}

}

Abhijit Sil