hello! i;m backing-up some avi files on a dvd-r media. i do not convert them into dvd's, just avi files on a dvd-iso format. they are written perfectly, but when i try to play them from the dvd-rom drive they produce skipping, jerky sound and video, and some of the files cannot be read at all. some of the files that can be read, when i copy them to the hard drive again, they are being played perfectly. i tried reading the disc from another drive but same problem occurs. thanking you in advance.