Parameter name: c 

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.ArgumentNullException: Collection cannot be null.

Parameter name: c

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: 

[ArgumentNullException: Collection cannot be null.

Parameter name: c]

   System.Collections.ArrayList..ctor(ICollection c) +9367527

   DotNetNuke.Entities.Portals.PortalController.GetPortals() +41

   DotNetNuke.Common.Initialize.CacheMappedDirectory() +40

   DotNetNuke.Common.Initialize.InitializeApp(HttpApplication app, Boolean& initialized) +174

   DotNetNuke.Common.Initialize.Init(HttpApplication app) +137

   DotNetNuke.HttpModules.RequestFilter.RequestFilterModule.FilterRequest(Object sender, EventArgs e) +210

   System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +148

   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +75

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Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.1022