SharePoint 2010 Sandbox Code

ULS Log Entries

01:25:18.94 	SPUCHostService.exe (0x0A8C)            	0x0D58	SharePoint Foundation         	Sandboxed Code Service        	fe8a	Medium  	 -  - Unable to activate worker process proxy object within the worker process: ipc://fe3bdb40-dbc3-4322-b772-b34a5752336c:7000	 
01:25:18.94 	SPUCHostService.exe (0x0A8C)            	0x0D58	SharePoint Foundation         	Sandboxed Code Service        	fe8c	Medium  	 -  - Error activating the worker process manager instance within the worker process. - Inner Exception: System.InvalidOperationException: Unable to activate worker process proxy object within the worker process: ipc://fe3bdb40-dbc3-4322-b772-b34a5752336c:7000     at Microsoft.SharePoint.UserCode.SPUserCodeWorkerProcess.CreateWorkerProcessProxies()	 
01:25:18.94 	SPUCHostService.exe (0x0A8C)            	0x0D58	SharePoint Foundation         	Sandboxed Code Service        	ei0t	Medium  	 - Process creation/initialization threw an exception. Stopping this process. "ipc://fe3bdb40-dbc3-4322-b772-b34a5752336c:7000"	 
01:25:19.05 	SPUCHostService.exe (0x0A8C)            	0x0D58	SharePoint Foundation         	Sandboxed Code Service        	fe87	Medium  	 -  - Error activating the worker process manager instance within the worker process. - Starting worker process threw - Inner Exception: System.InvalidOperationException: Unable to activate worker process proxy object within the worker process: ipc://fe3bdb40-dbc3-4322-b772-b34a5752336c:7000     at Microsoft.SharePoint.UserCode.SPUserCodeWorkerProcess.CreateWorkerProcessProxies()	 

WebPart Code

using System;
using System.ComponentModel;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using Microsoft.SharePoint;
using Microsoft.SharePoint.WebControls;

namespace _005_SandBoxWebpart.WP_HelloWorld
{
    [ToolboxItemAttribute(false)]
    public class WP_HelloWorld : WebPart
    {
        Label lblName = new Label() { ID = "lblName", Visible = true, Text = "You Name Plese: " };
        Button brtnSayHello = new Button() { ID = "btnSayHello", Visible = true, Text = "Greet" };
        TextBox txtName = new TextBox() { ID = "txtName", Visible = true, };

        protected override void CreateChildControls()
        {
           

            brtnSayHello.Click += new EventHandler(brtnSayHello_Click);

            Controls.Add(lblName);
            Controls.Add(txtName);
            Controls.Add(brtnSayHello);
        }

        void brtnSayHello_Click(object sender, EventArgs e)
        {
            string JSScript = "alert('Hi {0}, greetings from sandboxed webpart.');";

            JSScript = string.Format(JSScript,txtName.Text);
            ScriptManager.RegisterStartupScript(this, this.GetType(), "HelloWorldScript", JSScript, true);
        }
    }
}