I have upgraded out site from 3.01.01 to 4.5.3  I followed the steps at
http://www.mitchelsellers.com/blogs/a...

when i ran the install.aspx it came back with this:
Microsoft (R) Visual Basic Compiler version 8.0.50727.3053
for Microsoft (R) .NET Framework version 2.0.50727.3615
Copyright (c) Microsoft Corporation.  All rights reserved.

C:\Inetpub\wwwroot\OSTwo5\App_Code\Migrated\admin\containers\Stub_icon_ascx_vb.vb(16) : error BC30560: 'SkinObjectBase' is ambiguous in the namespace 'DotNetNuke.UI.Skins'.

        Inherits UI.Skins.SkinObjectBase
                 ~~~~~~~~~~~~~~~~~~~~~~~
C:\Inetpub\wwwroot\OSTwo5\App_Code\Migrated\admin\scheduling\ViewScheduleHistory_ascx_vb_ScheduleHistorySortStartDate.vb(25) : error BC30560: 'ScheduleHistoryItem' is ambiguous in the namespace 'DotNetNuke.Services.Scheduling'.

            Return CType(y, ScheduleHistoryItem).StartDate.CompareTo(CType(x, ScheduleHistoryItem).StartDate)
                            ~~~~~~~~~~~~~~~~~~~                                                             
C:\Inetpub\wwwroot\OSTwo5\App_Code\Migrated\admin\scheduling\ViewScheduleHistory_ascx_vb_ScheduleHistorySortStartDate.vb(25) : error BC30560: 'ScheduleHistoryItem' is ambiguous in the namespace 'DotNetNuke.Services.Scheduling'.

            Return CType(y, ScheduleHistoryItem).StartDate.CompareTo(CType(x, ScheduleHistoryItem).StartDate)
                                                                              ~~~~~~~~~~~~~~~~~~~           
C:\Inetpub\wwwroot\OSTwo5\App_Code\components\Exceptions\ModuleLoadException.vb(29) : error BC30560: 'BasePortalException' is ambiguous in the namespace 'DotNetNuke.Services.Exceptions'.

        Inherits BasePortalException
                 ~~~~~~~~~~~~~~~~~~~
C:\Inetpub\wwwroot\OSTwo5\App_Code\components\Exceptions\ModuleLoadException.vb(34) : error BC30560: 'ModuleInfo' is ambiguous in the namespace 'DotNetNuke.Entities.Modules'.

        Private m_ModuleConfiguration As ModuleInfo
                                         ~~~~~~~~~~
C:\Inetpub\wwwroot\OSTwo5\App_Code\components\Exceptions\ModuleLoadException.vb(50) : error BC30560: 'ModuleInfo' is ambiguous in the namespace 'DotNetNuke.Entities.Modules'.

        Public Sub New(ByVal message As String, ByVal inner As Exception, ByVal ModuleConfiguration As ModuleInfo)
                                                                                                       ~~~~~~~~~~
C:\Inetpub\wwwroot\OSTwo5\App_Code\components\Exceptions\ModuleLoadException.vb(86) : error BC30284: sub 'GetObjectData' cannot be declared 'Overrides' because it does not override a sub in a base class.

        Public Overrides Sub GetObjectData(ByVal info As SerializationInfo, ByVal context As StreamingContext)
                             ~~~~~~~~~~~~~                                                                   
C:\Inetpub\wwwroot\OSTwo5\App_Code\components\Modules\PaWriter.vb(50) : error BC30560: 'PaLogger' is ambiguous in the namespace 'DotNetNuke.Modules.Admin.ResourceInstaller'.

        Private _ProgressLog As New PaLogger
                                    ~~~~~~~~
C:\Inetpub\wwwroot\OSTwo5\App_Code\components\Modules\PaWriter.vb(66) : error BC30560: 'PaLogger' is ambiguous in the namespace 'DotNetNuke.Modules.Admin.ResourceInstaller'.

        Public ReadOnly Property ProgressLog() As PaLogger
                                                  ~~~~~~~~
C:\Inetpub\wwwroot\OSTwo5\App_Code\components\Modules\PaWriter.vb(76) : error BC30560: 'DesktopModuleInfo' is ambiguous in the namespace 'DotNetNuke.Entities.Modules'.


And may more errors.
Any idea where i should start in trying to get this site running again?

Thanks for any help.