Back up dvds do not play on other drives

Dvds recorded on new external USB I/O Magic TSST Corp. cd/dvdw -SH-S182M drive will not play on other older internal DVD-ROM drives.
Any ideas on why?

There’s a long list of possible reasons. Many older DVD-ROM drives do not support all recordable formats. That would be the best place to start. In general, DVD-R is more widely supported on old ROM drives. YMMV.

I suspect that you should use Nero cd-dvd speed’s bitsetting feature to change your blank media booktype to dvd-rom before you burn movies on them.