System.Web.HttpException The type 'WebService.WebService' is ambiguous: it could come from assembly A or B

The type 'WebService.WebService' is ambiguous: it could come from assembly 'C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\be16cd76\fad287b\App_Code.rwr4wlid.DLL' or from assembly 'C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\be16cd76\fad287b\App_WebReferences.2_hrkewk.DLL'. Please specify the assembly explicitly in the type name.

I have the same error message when I run the WebService.asmx local except that it points to an asp.net temp folder.

There are two sites, each having a WebService, each has their own port no.

The live sites are on a shared server.

The WebService.asmx file looks the same on each site:

<%@ WebService Language="C#" CodeBehind="~/App_Code/WebService.cs" Class="WebService.WebService" %>

The WebService.cs class is also the same, here are the first few lines:

namespace WebService
{
    /// <summary>
    /// Web Service Namespace="http://developer.intuit.com/"
    /// Web Service Name="WebService"
    /// Web Service Description="Sample WebService in ASP.NET to 
    /// demonstrate QuickBooks WebConnector"
    /// </summary>
    [WebService(
         Namespace = "http://developer.intuit.com/",
         Name = "WebService",
         Description = "Sample WebService in ASP.NET to demonstrate " +"QuickBooks WebConnector")]

    // Important Note: 	
    // You should keep the namespace as http://developer.intuit.com/ for all web 
    // services that communicates with QuickBooks Web Connector. 


    public class WebService : System.Web.Services.WebService
    {
        #region GlobalVariables
        System.Diagnostics.EventLog evLog = new System.Diagnostics.EventLog();
        public int count = 0;
        public ArrayList req = new ArrayList();
        public static int theprovider = -1;

        #endregion

        #region Constructor
        public WebService()
        {
            //CODEGEN: This call is required by the ASP.NET 
            //Web Services Designer
            InitializeComponent();
            // Initializing EventLog for logging
            initEvLog();
        }
        #endregion

        #region AutoGeneratedMethods
        //Required by the Web Services Designer 
        private IContainer components = null;

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
        }

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        protected override void Dispose(bool disposing)
        {
            if (disposing && components != null)
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #endregion


        #region WebMethods

The error message says "Please specify the assembly explicitly in the type name."

No clue what this means. Where and how?