Word document preview error

Hello, I want to see a preview of my translated document, but get the following error message: Word document prview error   Could not load file or assembly Microsoft.Office.Interop.Word, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c or one of iets dependencies. The system cannot find the file specified.

I don't understand this message. What can I do to get the preview?

Thanks in advance, Nicole