"The language of this installation package is not supported by your system" error message when you try to take a SharePoint 2010 external list offline to Outlook 2010

Applies to: Microsoft SharePoint Foundation 2010SharePoint Server 2010

Symptoms

Consider the following scenario:
  • You install Microsoft SharePoint Server 2010 on a server, and you have an enterprise access license enabled.
  • On a Windows XP-based computer, you install Microsoft Office 2010.
  • Office 2010 is localized to a different language than is used by Windows XP.
  • On the Windows XP-based computer, you install the Office 2010 Language Pack for a third language.
  • On the Windows XP-based computer, you install the .NET Framework 3.5 Service Pack 1 (SP1).
  • On the Windows XP-based computer, you change the Office 2010 language locale to match the language of the Office 2010 Language Pack.
  • On the SharePoint 2010 server, you import an External Content type that is mapped to an Office item, and then you create an external list that uses this External Content type. 
When you try to take the external list offline to Outlook 2010 in this scenario, you receive the following error message:

The language of this installation package is not supported by your system.

If you try to take the list offline after receive this error, you receive the following error message:

.NET Framework 3.5 is not installed.

Workaround

To work around this issue, change the Windows XP language locale to match the language that is being used by Office 2010. To do this, follow these steps:
  1. Click Start, point to Settings, and then click Control Panel.
  2. Double-click the Regional Options icon.
  3. In the Regional Options dialog box, click to select the check box for the language to which you want to change.  
  4. Click the Set default button.
  5. In the Select System Local dialog box, click the language that you want, and then click OK.
  6. In the Regional Options dialog box, click Apply.
  7. Click Yes when you are prompted with the following message:  
    Required files are already installed on your hard disk. Setup can use these existing files, or Setup can recopy them from your original Windows CD-ROM or from a network share. 

    Would you like to skip the file copying and use the existing files? (If you click No, you will be prompted to insert your Windows CD-ROM or to supply a different location where the files can be found.)  
  8. When you are prompted to restart your computer, click Yes.