I have an NEC, think though it is the 2400A (4X -/+ drive)..
DMA, don't worry about that, it should be set to Ultra DMA by XP as a default.
My drive wouldn't recongnize or burn anything to a spindle of 'no name' DVD's and drove me nuts. I tried a few hacker type firmwares, finally just tried NEC's own, my old one was 1.08, using NEC's 1.09, it not only recongnises the blanks, but makes perfect working copies that so far work in 3 different stand alones..
Nero's disk utility will let you know what actual brand, speed and type (+/-) DVD you are using. Can't find it now, might have been on this site, but there was a posting showing what disks were supported by what firmware versions. Make sure you are covered. Also, be sure to try the legit firmware first, I had no luck at all with the 'enhanced' copies and 100% luck with NEC's own.
Try DVDFab, it is useless for doing custom things as it has vertually no user options, however it did an excellent job on compression to 1 DVD and extreemly good job at splitting a DVD to 2 disks (no compression and keeping all the features and different sound tracks). I havn't used your program so I don't know if it is part of your problem or not. There are also web sites that track how well different media brands and types play on different stand alone players, I seem to be blessed with my Toshiba 1200 as it appears to play almost anything.
As to being seen by XP, things that come to mind..
Start with a known original NEC firmware..
Try the drive as 'master/alone' without sharing the IDE port with either your HD or another CD drive..
Make sure you are using a UDMA cable, that ground wire between each data wire is important..
XP's built in drivers should be the right choice but check the NEC website incase they have better ones..
Hope some of that helps.