Hello, You must save all four files you get in each e-mail. The NL you see in the file name is not the file extention. The four files you save from each e-mail will have the following extentions. .ncx .opf .smil and .xml After you've saved the files to your hard drive open the book port transfer program and navigate to the folder where you saved your files. The Book Port will only recognize the .opf file. This is the file you need to transfer to the Book Port so it can decode and transfer the other three files. Note that you must have all four files in the same folder so Book Port can access them. Hope this helps. Frank Brown