I had compiled the latest version of source code and my colleague tried to deploy to web server. But the server kept having the error as below. After rollback to previous version, it works fine.

The compiled codes work perfectly in testing server, which is also running Windows Server 2003. May I know the possible cause of this error?

Server Error in '/MyApp' Application. 
________________________________________
Compilation Error 
Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately. 

Compiler Error Message: BC30560: 'Default' is ambiguous in the namespace 'ASP'.

Source Error:


Line 43:         Public Sub New()
Line 44:             MyBase.New
Line 45:             If (Global.ASP.[Default].__initialized = false) Then
Line 46:                 Global.ASP.[Default].__initialized = true
Line 47:             End If

Source File: C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\App_Theme_Default.klj61xen.0.vb    Line: 45 

Show Detailed Compiler Output:

c:\windows\system32\inetsrv> "C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\vbc.exe" /t:library /utf8output /R:"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\assembly\dl3\0e5991fe\0021f4ae_c465c901\App_Theme_Default.DLL" /R:"C:\WINDOWS\assembly\GAC_MSIL\System.Web.Extensions\1.0.61025.0__31bf3856ad364e35\System.Web.Extensions.dll" /R:"C:\WINDOWS\assembly\GAC_32\System.Data\2.0.0.0__b77a5c561934e089\System.Data.dll" /R:"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\assembly\dl3\f5a53c32\00f70fef_5228c901\MyApp.Core.DLL" /R:"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\assembly\dl3\b4e7cc48\007d7395_9615c701\Microsoft.ReportViewer.WinForms.DLL" /R:"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\assembly\dl3\df1cb776\0013b333_9615c701\Microsoft.ReportViewer.WebForms.DLL" /R:"C:\WINDOWS\assembly\GAC_MSIL\System.ServiceModel\3.0.0.0__b77a5c561934e089\System.ServiceModel.dll" /R:"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\assembly\dl3\4443d51c\00d8749f_c465c901\MyApp.Business.DLL" /R:"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\assembly\dl3\94c22af1\00e46e27_aaf2c801\AjaxControlToolkit.DLL" /R:"C:\WINDOWS\assembly\GAC_MSIL\System.Drawing\2.0.0.0__b03f5f7f11d50a3a\System.Drawing.dll" /R:"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\assembly\dl3\1b6ad857\0019583c_9715c701\Microsoft.ReportViewer.Common.DLL" /R:"C:\WINDOWS\assembly\GAC_MSIL\System.Xml\2.0.0.0__b77a5c561934e089\System.Xml.dll" /R:"C:\WINDOWS\assembly\GAC_MSIL\System.Web.Services\2.0.0.0__b03f5f7f11d50a3a\System.Web.Services.dll" /R:"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\assembly\dl3\6bb4240b\001b822f_b375c701\PageMethods.DLL" /R:"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\assembly\dl3\0eca42cd\00d8749f_c465c901\MyApp.Data.DLL" /R:"C:\WINDOWS\assembly\GAC_MSIL\System.Web.Extensions.Design\1.0.61025.0__31bf3856ad364e35\System.Web.Extensions.Design.dll" /R:"C:\WINDOWS\assembly\GAC_MSIL\System.Runtime.Serialization\3.0.0.0__b77a5c561934e089\System.Runtime.Serialization.dll" /R:"C:\WINDOWS\assembly\GAC_MSIL\System.Configuration\2.0.0.0__b03f5f7f11d50a3a\System.Configuration.dll" /R:"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\assembly\dl3\66f89cbd\009a60ab_c465c901\App_Code.DLL" /R:"C:\WINDOWS\assembly\GAC_MSIL\System.Web.Mobile\2.0.0.0__b03f5f7f11d50a3a\System.Web.Mobile.dll" /R:"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\assembly\dl3\7b06f25a\009a60ab_c465c901\App_global.asax.DLL" /R:"C:\WINDOWS\assembly\GAC_32\System.Web\2.0.0.0__b03f5f7f11d50a3a\System.Web.dll" /R:"C:\WINDOWS\assembly\GAC_32\System.EnterpriseServices\2.0.0.0__b03f5f7f11d50a3a\System.EnterpriseServices.dll" /R:"C:\WINDOWS\assembly\GAC_MSIL\System.IdentityModel\3.0.0.0__b77a5c561934e089\System.IdentityModel.dll" /R:"C:\WINDOWS\assembly\GAC_MSIL\System\2.0.0.0__b77a5c561934e089\System.dll" /out:"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\App_Theme_Default.klj61xen.dll" /D:DEBUG=1 /debug+ /define:_MYTYPE=\"Web\" /imports:Microsoft.VisualBasic,System,System.Collections,System.Collections.Specialized,System.Configuration,System.Text,System.Text.RegularExpressions,System.Web,System.Web.Caching,System.Web.SessionState,System.Web.Security,System.Web.Profile,System.Web.UI,System.Web.UI.WebControls,System.Web.UI.WebControls.WebParts,System.Web.UI.HtmlControls  "C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\App_Theme_Default.klj61xen.0.vb" "C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\App_Theme_Default.klj61xen.1.vb"


Microsoft (R) Visual Basic Compiler version 8.0.50727.832
for Microsoft (R) .NET Framework version 2.0.50727.832
Copyright (c) Microsoft Corporation.  All rights reserved.

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\App_Theme_Default.klj61xen.0.vb(45) : error BC30560: 'Default' is ambiguous in the namespace 'ASP'.

            If (Global.ASP.[Default].__initialized = false) Then
                ~~~~~~~~~~~~~~~~~~~~                            
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\App_Theme_Default.klj61xen.0.vb(46) : error BC30560: 'Default' is ambiguous in the namespace 'ASP'.

                Global.ASP.[Default].__initialized = true
                ~~~~~~~~~~~~~~~~~~~~                     
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\MyApp\574a9c69\583141c0\App_Theme_Default.klj61xen.1.vb(31) : error BC30560: 'Default' is ambiguous in the namespace 'ASP'.

            Return New ASP.[Default]
                       ~~~~~~~~~~~~~

Show Complete Compilation Source:

Line 1:    '------------------------------------------------------------------------------
Line 2:    ' <auto-generated>
Line 3:    '     This code was generated by a tool.
Line 4:    '     Runtime Version:2.0.50727.832
Line 5:    '
Line 6:    '     Changes to this file may cause incorrect behavior and will be lost if
Line 7:    '     the code is regenerated.
Line 8:    ' </auto-generated>
Line 9:    '------------------------------------------------------------------------------
Line 10:   
Line 11:   Option Strict Off
Line 12:   Option Explicit On
Line 13:   
Line 14:   Imports Microsoft.VisualBasic
Line 15:   Imports System
Line 16:   Imports System.Collections
Line 17:   Imports System.Collections.Specialized
Line 18:   Imports System.Configuration
Line 19:   Imports System.Text
Line 20:   Imports System.Text.RegularExpressions
Line 21:   Imports System.Web
Line 22:   Imports System.Web.Caching
Line 23:   Imports System.Web.Profile
Line 24:   Imports System.Web.Security
Line 25:   Imports System.Web.SessionState
Line 26:   Imports System.Web.UI
Line 27:   Imports System.Web.UI.HtmlControls
Line 28:   Imports System.Web.UI.WebControls
Line 29:   Imports System.Web.UI.WebControls.WebParts
Line 30:   
Line 31:   Namespace ASP
Line 32:       
Line 33:       <System.Runtime.CompilerServices.CompilerGlobalScopeAttribute()>  _
Line 34:       Public Class [Default]
Line 35:           Inherits Global.System.Web.UI.PageTheme
Line 36:           
Line 37:           Private __controlSkins As System.Collections.Specialized.HybridDictionary = New System.Collections.Specialized.HybridDictionary(0)
Line 38:           
Line 39:           Private __linkedStyleSheets() As String = New String() {"~/App_Themes/Default/css/All.css"}
Line 40:           
Line 41:           Private Shared __initialized As Boolean
Line 42:           
Line 43:           Public Sub New()
Line 44:               MyBase.New
Line 45:               If (Global.ASP.[Default].__initialized = false) Then
Line 46:                   Global.ASP.[Default].__initialized = true
Line 47:               End If
Line 48:           End Sub
Line 49:           
Line 50:           Protected Overrides ReadOnly Property AppRelativeTemplateSourceDirectory() As String
Line 51:               Get
Line 52:                   Return "/MyApp/App_Themes/Default/"
Line 53:               End Get
Line 54:           End Property
Line 55:           
Line 56:           Protected Overrides ReadOnly Property ControlSkins() As System.Collections.IDictionary
Line 57:               Get
Line 58:                   Return Me.__controlSkins
Line 59:               End Get
Line 60:           End Property
Line 61:           
Line 62:           Protected Overrides ReadOnly Property LinkedStyleSheets() As String()
Line 63:               Get
Line 64:                   Return Me.__linkedStyleSheets
Line 65:               End Get
Line 66:           End Property
Line 67:       End Class
Line 68:   End Namespace
Line 69:   

________________________________________
Version Information: Microsoft .NET Framework Version:2.0.50727.832; ASP.NET Version:2.0.50727.832