Hi, I’m experiencing the same problem with you. I’m using NEC 2500a as well and have been trying different media + and -R. First of all, I heard a lot of rumour about NEC 2500a as a bad reader. Second of all, try to see if you have scratches on your burned DVDs. The backup DVDs can be played in home DVD player correctly because they have error correction. It is different from your DVD drive that read the files as data. I have experienced that the freshly burned DVD without scratch can be copied to HD just like the commercial DVD, but after a while and there come scratches then it started to give me “data cyclic redundancy error”. It could be because of bad media. Most of the DVDs that give me that error are from RitekG04, and so far as I use Teon -R (CMC) and Ridata +R (RICOHJPNR01) I haven’t gotten any of this problem. Well, after I knew about this, I tried not to scratch my discs.
Solution: try to check your burned DVD with programs that I used: DVDInfoPro or CDSpeed from Nero 6. For some reason the DVDInfoPro gives me some read error most of the time even though the disc is fine (don’t know why). Lately I check my DVDs with CDSpeed and you can tell when the data transfer curve is good, then your disc is ok, but if it shows major drops, then you would probably consider a different media.
Note: Those two media work really good in my NEC 2500a, so it should work as good as mine in your burner too.