How can I fix a wmv file that is not indexed ?

I saved a slide show that I made with Photoshop to a wmv file and tried to burn it to a DVD using Windows DVD Maker in Windows 7 unsuccessfully. I have successfully made slide shows about 15 times in the past and have had no problem. This time when I try to load the wmv file to the DVD Maker I get a message telling me that my wmv is not indexed and cannot be imported.

What does this mean and how can I fix it ? The file is made entirely of jpg photos.