Try to copy several really big files (several hundreds of MB, several GB in total) from the source of your DVD files to the destination where you usually save the ISO file. Compare the files and check if they are corrupted. If they are, the corruption occurs when reading/writing from/to your hard disc(s).
You might also want to check the cable connecting your 716A with the IDE controller. It should not be longer than 45cm (usually 60cm work as well, but the specification allows only 45cm), and for UDMA66 or above, a cable with 80 wires is needed, otherwise you will get data corruption while burning for sure.
Check if your IDE cable is perhaps defective by using a different one.
And finally, tell us more about your mainboard, IDE drives and controllers, etc.