Most current DVD stand alone player can play DVD+R, so it's not the player's fault. If you wanna blame, put it on DVDXCopy, the biggest load of crap in the history of DVD backup software.... with that said, lets get your DVD backup.
1) Google for DVDShrink, download, and unzip it.
2) Put in DVD you want to backup to DVD-ROM drive.
3) Start DVDShrink, select customize, go into each VST set and choose what compression lvl you want. You want the final size to be 4.38GB, which is how much a 4.7GB DVD blank will hold. Push start when you're satisfy w/ your selection.
a. In most cases, you'll have to use at least lvl 1 compression on the main movie. I like to use lvl 1 compression on the menu too. Also, I would take out Dolby Stereo 2.0 and keep DD 5.1 and DTS (if available) sound tracks. Uncheck or select Still movie for all the other stuff. If you want subtitle, keep only the English part.
4) The compressed files will be stored on your HD.
5) Start Nero (lastest version), put blank DVD+R/-R in DVD writer, select DVD from the pull down menu and choose DVD-Video, name the disc and left everything else at default.
6) At the file selection window, you'll see an Audio and Video folder for the DVD. Open the Video folder and drag the compressed files you made w/ DVDShrink earlier.
7) Write the DVD. You've just finished backing up your DVD. Yes, it's that simple and free, since DVDShrink is a freeware, and Nero comes w/ almost all CD Writers.
BTW, which DVD writer are you using?