Error al instalar DotNetNuke4 !!

[byle]

Hola!

Estoy intentando instalar dotnetnuke 4.3 y una vez ya he creado directorios virtuales, bases de datos i usuarios i tocado todos los permisos voy al navegador para ejecutar dotnetnuke i me sale lo del upgrade y al darle a access your portal me sale el siguiente error



Server Error in '/DotNetnuke2' Application.
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Object reference not set to an instance of an object.

Description: An unhandled exception occurred during the execution of
the current web request. Please review the stack trace for more
information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set
to an instance of an object.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:


[NullReferenceException: Object reference not set to an instance of an object.]
DotNetNuke.Entities.Portals.PortalSettings.GetPort alSettings(Int32 TabId, PortalAliasInfo objPortalAliasInfo) +125

DotNetNuke.Entities.Portals.PortalSettings..ctor(I nt32 tabId, PortalAliasInfo objPortalAliasInfo) +83

DotNetNuke.HttpModules.UrlRewriteModule.OnBeginReq uest(Object s, EventArgs e) +3908
System.Web.SyncEventExecutionStep.System.Web.HttpA pplication.IExecutionStep.Execute() +92

System.Web.HttpApplication.ExecuteStep(IExecutionS tep step, Boolean& completedSynchronously) +64




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Version Information: Microsoft .NET Framework Version:2.0.50727.42; ASP.NET Version:2.0.50727.42




Alguien sabe a que puede deberse?? Llevo casi una semana probando i no consigo nada!!!

Saludos!!