You should check the "sha1sum" of the downloaded iso's first before burning them to disc. That will tell you if the iso is good and not corrupted before burning the image to a disc. That method works for me and it will give you confidence knowing that your downloaded file is not corrupted.
If you are using Nero/Windows you should download and use ImgBurn to burn your iso to disc, in Windows it works well and you just right click on the iso and choose ImgBurn put in a blank disc and burn.
Here are a couple of links, one to SlavaSoft
for a sha1sum utility and the other to ImgBurn