What is this error?

PLEASE HELP, I can not save any thing on Admin/Site Setting or Apply Google OpenID Authentication or .... Something happen on my Website after upgrading from 7.3.1 to 7.3.2 ....  Also I change My Default Site Name directly by SQL server, if it is cause, I tell just for more help to find cause to get this error....  please help... I get 25 Error Exception when I apply some change on site settings and result was no changes apply.

System.ArgumentException: An item with the same key has already been added.
   at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
   at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
   at DotNetNuke.Entities.Portals.PortalController.GetPortalSettingsDictionaryCallback(CacheItemArgs cacheItemArgs)

Thanks Sebastian

It's Fixed. :)

Sebastian,

I did manage to get rid of the error in an instance with just one portal, using just one language (nl).

But what if an instance contains many portals of which some are multiple language portals? Do I delete all rows in PortalSetings with the same SettingName value, except for the ones having multiple languages?

I'm running into urlrewriting that doesn't work anymore, so it is kinda urgent.

Thanks,
Keston