Sorry didn't have much time to expand on this the other day.
Some film companies use copy protection system to try to stop people copying from pre-recorded tapes - As Katyratbag says Disney is a good example - they use Macrovision for video
Macrovision implants a signal that messes with the automatic gain control on the recorder and messes up the recording.
Not all film companies use copy protection on video, some feel that it's not worth paying the royalties to Macrovision and are more concerned with copy protection on DVD where perfect bit for bit copies could be made and protecting their newest theatre releases.
Anyway if you have seperate DVD and Video you can connect them with devices that strip out macrovision and allow you to record protected content
here's an example:
http://www.multi-region.co.uk/dvd_macrovision. php
The hole on the back of a video casette just tells a video recorder whether or not it can overwrite the contents of a tape and so is a bit of a red herring for what you want to do.
As for recording format - different DVD makers favor different formats but pretty much any recorder will play a DVD-R
Hope this helps