There’s a major difference between RW (rewritable) and plain R (recordable) discs. The RW can often have problems in some DVD recorders where the R will work. This happens with either the +RW or -RW discs. Try using just the recordable (-R or +R) discs and see if it makes a difference.
Othewise, you’ve been screwed by the DRM police. Good luck. Buying a DVR that doesn’t have DRM is your only choice.
Have suggestions on a recorder?