Incompatible Media or Faulty Drive?

OK, I have 2 DVD writers, one is a Lite-On SHW-1635SX and the other is another external from I/O Magic. The problem is with RW media.

First up, DVD+RW (Sony 4x):

I got these Sony DVD+RWs, and basically the Lite-On can’t write to it. It gives me an error each time I try, even with erasing it in Nero. HOWEVER, my I/O Magic reads/writes just fine with it. Now here’s the weird part. If I write files to it with the I/O Magic, and put the disc in the Lite-On, it reads it fine! AND, if I now try to burn the disc, it works too!! What does this mean?? :eek: :confused:
Oh yeah it writes fine with DVD-Rs (Taiyo Yuden), and in the instruction book, Sony brand DVD+RWs are under the supported media list.

Second up, CD-RW (TDK 4x):

Basically, same sort of deal. If I try putting in media burned with my regular CD burner (Lite-On as well), it can’t read it and basically locks up itself as well as my system, and I have to use a pin to “manually” eject the CD. The I/O Magic reads the discs just fine. Now if I erase the data with any other drive, the Lite-On will now read/write to it, same deal as with the DVD+RW discs. Weird?? :confused:

So…does this mean the Lite-On is faulty?