Had a customer call today with the same issue.  The site has been running ok for about a month (installed since release of 4.06.02).

DotNetNuke Version: The DotNetNuke application version you are running	04.06.02
Data Provider: The provider name which is identified as the default data provider in the web.config file	SqlDataProvider
.NET Framework: The .NET Framework version which the application is running on - specified through IIS	2.0.50727.832
ASP.NET Identity: The Windows user account under which the application is running. This is the account which needs to be granted folder permissions on the server.	NT AUTHORITY\NETWORK SERVICE

I did as previously suggested.  I opened the web.config file and deleted some commented out code (sql express connection information) and ftp'd back up to the site.  Accessed the site and everything came back up.

Anyone come up with reasons why yet?  I have other customers out there with the same build.

Doug

hi all,

Dont know why, but there's no post on this for approximately one month or so. Has anyone found a solution? If yes, then please post it since there a couple of other threads running/ dissussing the same issue.

Meanwhile, while going through the stack trace and running through the code [the old fashion "find" way], I think i have found where the error is occuring, but am not sure whats the solution. The error that I got is as below.  I followed the stack and reached the DotNetNuke_04.05.05_Source\Library\Components\Tabs\TabInfo.vb file which gets populated with all the variables and values of a tab and there's only one collection among all the properties being filled up and that is at line 278

        <XmlArray("tabpermissions"), XmlArrayItem("permission")> Public Property TabPermissions() As Security.Permissions.TabPermissionCollection

Would this be the cause?  HELP...this is occurring on our PROD server!

[IndexOutOfRangeException: Index was outside the bounds of the array.]
   System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add) +1199395
   DotNetNuke.Entities.Tabs.TabController.FillTabInfo(IDataReader dr, Boolean CheckForOpenDataReader) +2255
   DotNetNuke.Entities.Tabs.TabController.GetTab(Int32 TabId, Int32 PortalId, Boolean ignoreCache) +220
   DotNetNuke.Entities.Portals.PortalSettings.VerifyPortalTab(Int32 PortalId, Int32 TabId) +317
   DotNetNuke.Entities.Portals.PortalSettings.GetPortalSettings(Int32 TabId, PortalAliasInfo objPortalAliasInfo) +2413
   DotNetNuke.Entities.Portals.PortalSettings..ctor(Int32 tabId, PortalAliasInfo objPortalAliasInfo) +83
   DotNetNuke.HttpModules.UrlRewriteModule.OnBeginRequest(Object s, EventArgs e) +2760
   System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +92

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

regards
harish

Chris' fix appears to be the most common one out there.  As far as I know, there is not a "solution" to this.  Only workarounds such as the one that Chris mentioned. 

That being said, I still have yet to experience this since upgrading my production environment to 4.06.02.  However, since this appears to be ASP.Net and cache related mostly, I do not think that that had a bearing on this.