Your Host and Admin Site Settings are Unavailable.
Issue
After upgrading to DNN 5.x you may receive a site settings is unavailable error on several of your admin and host setting pages.

Cause
This is a common issue after an upgrade and can usually be fixed with the following steps.

Resolution 1

1. Log into the site as host or another superuser account.
2. Go to Admin > Languages.
3. Click Edit Language under available locales.
4. Select English (United States) under language and click update and select the Enabled box
5. Recycle the App Pool by going to Host > Host Settings and click the Restart Application button
6. Confirm functionality of the host and admin settings.

Resolution 2
You will need to have Microsoft SQL Server Management Studio 2008 installed to complete these steps. Microsoft SQL Server Mangement Studio Express 2008 is available for free from Microsoft, and can be downloaded through this link:  http://www.microsoft.com/download/en/details.aspx?id=22985

Always back up the website before making any changes to the database . Shared hosting customers can do this through the Control Panel. Refer to Back Up Your Website Using Plesk. Dedicated server customers can back up the site either through the Plesk Control Panel, or through the Control Suite. Refer to How to Back Up a Domain Using Control Suite.

1. Log into the database through SQL Management Studio
2. Open the Portals table and find the PortalID of the portal you are working with.
3. Open the Languages table and find the LanguageID of the language you need.
4. Open the PortalLanguages table and add a new entry into the table using the PortalID and LanguageID above.  The PortalLanguageID will be autogenerated and the rest of the fields can be left at NULL.
5. Recycle the App Pool by logging into your site. Click on Host > Host Settings and click the Restart Application button.
6. Confirm functionality of the host and admin settings.