From Application Settings Overview:
"You cannot use application settings in an unmanaged application that hosts the .NET Framework. Settings will not work in such environments as Visual Studio add-ins, C++ for Microsoft Office, control hosting in Internet Explorer, or Microsoft Outlook add-ins and projects".

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>http://msdn.microsoft.com/en-us/library/a65txexh(VS.80).aspx
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>the owner of the DLL says to us:
>"app.config must be present in the application consuming the library and not in the library itself."
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>