If you copied the file to a DVD-RW using Windows Explorer, then you were
using some type of packet writing technology (e.g., UDF, DLA, DirectCD,
etc).
Unfortunately, there is no one standard.
If you had another computer with the same flavor of packet writing (same
vendor, same version), then the DVD-RW should be readable.
But, there is a sort of universal alternative that can read most CDs and
DVDs, no matter how they are written. It is called ISOBUSTER. Some
functions are free, although more advanced option require a small fee for a
license. The ability to detect and read optical media is among the free
functions, or was the last time I had to use it.
Go here, download and install, then read the help:
http://www.isobuster.com/
Also read their license strategy, that is, what is free and what is pay:
http://www.isobuster.com/license-models.php
Hint: ISOBUSTER can try to read a CD or DVD in several ways, but not all at
the same time. Thus, you may need to choose a mode, try it, choose another,
try it, etc. It will be obvious when you succeed.
Note that the default read mode is (or used to be) the same as Windows,
which will not help you, unless you try it on a write-once CD/DVD that was
properly closed (finalized). Your DVD-RW is likely not in that category.