www.makemkv.com

so far this program works great and im a paying customer, but two dvd disks that play in my player can't seem to rip because they say a 'navigation' error. do you know what that means?

Usually it means they have errors in the directory. You say they play "in your player"'; is that a different device than your computer? Can you play them on the computer?

You could try the different DVD Opening Modes.