I was successful in upgrading DNN from 4.9.x to 6.2.3 and the site actually came back up.

Now the issue is, under Page Functions, when i try to click on the pages setting link of a previously existing page, I get the following ERROR!

Error: is currently unavailable. DotNetNuke.Services.Exceptions.ModuleLoadException: Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index ---> System.ArgumentOutOfRangeException: Index was out of range.

WHAT HAPPENED?! How Do I Fix This?

Not sure if this is an issue with the old skin tokens from 4.9x  as this only occurs on pages created in the old 4.9.x. How do i fix this where i can modify the settings and etc.

Any thoughts on this would be great.

Looks like all pages created in DNN 4.9X or pre DNN 6.x upgrade Page Settings cannot be accessed. However if I create a NEW page using the same old Skin, then page settings Works... just not the old previously created pages... very strange. However editing the content work FINE just can't access Page Settings. After checking the event viewer here is what i find.

--------------------------------------------------------------------------------------
ModuleId: -1

ModuleDefId: -1

FriendlyName:
ModuleControlSource: DesktopModules/Admin/Tabs/ManageTabs.ascx

AssemblyVersion: 6.2.3

PortalID: 0

PortalName: classified

UserID: 1

UserName: classified

ActiveTabID: 84

ActiveTabName: IP Telephony

RawURL: /tabid/84/ctl/Tab/action/edit/Default.aspx

AbsoluteURL: /Default.aspx

AbsoluteURLReferrer: https://localhost/tabid/84/Default.aspx

UserAgent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:15.0) Gecko/20100101 Firefox/15.0.1

DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider

ExceptionGUID: 8a2e40bd-0e29-4361-a50a-546c1fe9e452

InnerException: Index was out of range. Must be non-negative and less than the size of the collection.

Parameter name: index

FileName:

FileLineNumber: 0

FileColumnNumber: 0

Method: System.Collections.ArrayList.get_Item

StackTrace:

Message: DotNetNuke.Services.Exceptions.ModuleLoadException: Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index ---> System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index at System.Collections.ArrayList.get_Item(Int32 index) at System.Web.UI.WebControls.ListItemCollection.get_Item(Int32 index) at DotNetNuke.Web.UI.WebControls.Extensions.ListControlExtensions.Select(ListControl control, String initial, Boolean findByText, Int32 fallbackIndex) at DotNetNuke.Modules.Admin.Tabs.ManageTabs.BindTabControls(TabInfo tab) at DotNetNuke.Modules.Admin.Tabs.ManageTabs.BindTab() at DotNetNuke.Modules.Admin.Tabs.ManageTabs.OnLoad(EventArgs e) --- End of inner exception stack trace ---
Source:
Server Name: MyCPU
-------------------------------------------------------------------------------------

Any Ideas?

Thank you Sebastian,  however, looks like DNN is being stubborn...

I cleared the cache and restarted the application.... and no success.

I'm still getting the Error issue on old pages created in DNN 4.9.X  when I click page settings.... but not an issue on new pages added "after" the upgrade.

Very discouraging but still trying to find a solution or cause to the problem.

To reproduce, Take an old DNN 4.9.X site and upgrade it to DNN 6.2.X. Then login and try to click on page settings. Thats when the page gives the error listed in this post.

Keep the ideas and suggestion coming... its going to be a really long night.