HI, I'm having trouble solving the exception below, I did try all the scripts / fixes and possible cuases and stil i'm not able to solve this one. It's only on one portal, the other two portals in this dnn are not affected by this. Is ther eanyone who can help me with this one. Some of the crucial admin pages are not accessible anymore.

AbsoluteURL:/Default.aspx

DefaultDataProvider:DotNetNuke.Data.SqlDataProvider, DotNetNuke

ExceptionGUID:9ac720fa-6fff-41b7-9ca6-281a7f3128e4

AssemblyVersion:7.4.1

PortalId:8

UserId:1

TabId:681

RawUrl:/nl-nl/Admin/Site-Settings

Referrer:http://nmng.ises-softpack.eu/nl-nl/

UserAgent:Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.124 Safari/537.36

ExceptionHash:LHo1GuNcMuLwIFgEhKD4Jw==

Message:An item with the same key has already been added.

StackTrace:

InnerMessage:An item with the same key has already been added.

InnerStackTrace:

   at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)    at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)    at DotNetNuke.Web.UI.WebControls.DnnSkinComboBox.OnLoad(EventArgs e)    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

Source:

FileName:

FileLineNumber:0

FileColumnNumber:0

Method:

Server Naam: IIS-SERVER