DVD won't play for newbie

I have recorded some DVD-R discs and they play in my Pioneer machine fine. However, they won’t play in other machines even though they are supposed to be compatible with DVD-Rs. I’m using Decrypter and DVD Shrink. Does anyone have a clue what I might be doing wrong in my recording process. Or perhaps have other suggestions.

Sounds like a media problem - what media are you using?

I don’t have one here at the office but I believe it is Maxell DVD-R.