After fully converting, i am getting disc errors more frequently...plz help, need advice

I use 'ConvertXtodvd' and it will go through the whole converting process and complete....but here lately one out of about every 3 it will come up as disc error in the dvd player yet plays fine in the computer with no glitches. I realize some file can be corrupt..but this many? In the past i almost never had a disc error when converting, it seems to be happening more often which is fusterating considering it takes me an hour & a half to 2 hours for each convert. I am puzzled...is it the files or is it in my programming. I have a fairly new 'Vortex' gaming computer which has been re-formatting with plenty of free space, i delete all files after done to keep hard-drive from getting clogged, i disconnect internet to shut down any possible background programs that may interfere. Is there something I am possibly missing here....do i need some sort of tool to fix avi files after download..and if so, what are some good avi repair programs? And I am not familiar with any avi repair tools, looking for something simple if thats what the problem truly is. Thank you for reading and plz give me some advice.