Created Unassigned: Null ref error on import [2900]

I get a null reference error when trying to import. I'm guessing that's because Excel isn't installed on the machine, but that's a total swag. Would be nice if the app were decoupled from an Excel installation. At least notify user if Excel dependency is missing.


Screenshot:
http://i.imgur.com/CdzUYk1.png


Stack:
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************** Exception Text **************
System.NullReferenceException: Object reference not set to an instance of an object.
at ResourceManager.Converter.XlsxConverter.Import(String filePath)
at System.Windows.Forms.FileDialog.HandleVistaFileOk(IFileDialog dialog)


************** Loaded Assemblies **************