DVD+R and DVD+RW
DVD+R is a non-rewritable format and it is compatible with about 89% of all DVD Players and most DVD-ROMs.
DVD+RW is a rewritable format and is compatible with about 79% of all DVD Players and most DVD-ROMs.
DVD+R and DVD+RW supports single side 4.37 computer GB* DVDs(called DVD-5) and double side 8.75 computer GB* DVDs(called DVD-10).
These formats are supported by the DVD+RW Alliance
the above info i got from Ultra DVD creator help.
that may explain why dvd RW is not playing in all drives.