Hey mike.tuttle, bottom line.
You can convert most videos into a compatible format faster than you can post a question and find a solution in this forum. Occasionally, there will always be videos that are incompatible for one reason or another. If you edit a lot of videos, it's best to familiarize yourself with video conversion. There are a lot of free programs to do this.
I use Freemake myself. http://www.freemake.com/
See Image Below, Click to Enlarge
Others swear by Handbrake " I've used it myself" but it has a confusing UI for a lot of people. Especially if they are unfamiliar with the program.